Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Architect1776 Loc: In my mind

Great upgrade and gets you into the 21st century.
https://www.bhphotovideo.com/c/product/1461748-REG/nikon_z_6_mirrorless_digital.html

With the FTZ adapter you can mount all your old F lenses and new ones will AF as well.
https://www.bhphotovideo.com/c/search?Ntt=nikon%20ftz%20mount%20adapter&N=0&InitialSearch=yes&sts=ps

All under $2,000 yet pro quality.
Allows growth into the future as well so you are not stuck with old tech which is on a dead end path.

ronpier Loc: Poland Ohio

Nothing wrong with upgrading but don’t be disappointed if your image quality isn’t any better than that of your D3300. I have a D3400. 24mp, Expeed 4 Processor, 5 FPS. Doesn’t have the bells and whistles that the “high end” models have but the images sure are nice. Your D3300 IMO is definitely not old and outdated. I would look at upgrading a few lenses instead if you haven’t already done so.

Ched49 Loc: Pittsburgh, Pa.

This reply is exactly right, your present camera is not outdated. Without us knowing what you like to shoot, this is your best option. Learn everything you can about your D3300 first then you can decide what you want to upgrade in.

shutterbob Loc: Tucson

Nikon D7500. It has most of the worthwhile features of the D500 without the price, and unlike the 500 has a built in flash. And since you are budget concious, all of the lenses that work with your 3300 will work just fine on the 7500, unlike a D750 (full frame) or a Z50 (requires a FTZ adapter). I have a D750 & z50 but still love my 7500.

IDguy Loc: Idaho

Z50/w 2 lens kit and FTZ will make you happy.

The EVF is a huge leap forward. Things like eye detection and focus peaking will amaze.

Paul Diamond Loc: Atlanta, GA, USA

Just read thru the replies. My suggestion - take your time, decide what you like about your D3300 and what you want to do better for current photos and ones you want to take in the future.

Some years ago I upgraded from a d3200 to D800E then D850. Not all want the added complications of being able to select all settings in an D8 series camera. But, if you now have the kit lenses for your D3300, you will probably want to upgrade to higher resolution lenses regardless of which camera you choose. Look at used in good/very good condition with a return privilege for you to test them.

SteveR Loc: Michigan

I second tdozier's thought. This is an absolutely fabulous camera. It has everything the D500 has except autofocus capability that the D500 shares with the D5. It has fantastic low-light capability and the same processor as the D500 and D5, allowing it to shoot at 7-8 fps. The D7500 is nice and compact compared to the D500, however. If you are shooting a lot of sports or moving objects, though, the autofocus of the D500 may be worth the extra dollars and would still be under $2000. I would recommend staying with crop sensor cameras. The cost of really good lenses for full frame cameras are more than the cameras!!!

I bought this camera for my daughter and it's perfect for her. She takes great photos with it.

Architect1776 Loc: In my mind

amfoto1 Loc: San Jose, Calif. USA

First decide if you want to "go full frame" or stick with APS-C format cameras. Each format has it's pluses and minuses. If you want to "go full frame", depending upon what you've got there's good chance you'll also need to update your lens kit. While you can use DX (crop sensor) lenses on a full frame camera, it makes little sense to do so because you're images will need to be cropped and you'll just be wasting many of the benefits of the full frame camera you just paid extra to buy.

It depends upon what you shoot and how you shoot it. If you use telephoto lenses a lot, it would probably be best to stick with an APS-C camera like you have now. Crop sensor (DX in Nikon-speak) cameras make telephoto lenses even more powerful. But if you are a wide angle shooter, a full frame (FX) camera would be a better bet. FX also can be better for low light shooting, as they tend to have less digital noise issues.

After deciding which format you want, then you have to choose between sticking with a DSLR or going with a new mirrorless cameras. Once again, each type of camera has its pluses and minuses. DSLRs tend to be less expensive, get more shots per battery charge, but also bigger and heavier. There also are far more lenses for DSLRs than there are for mirrorless, so far. This is gradually changing, but for now it's also possible to use DSLR lenses on a mirrorless camera via an adapter (the opposite isn't possible... mirrorless lenses will never be usable on DSLRs). Mirrorless have some neat tricks too. Their electronic viewfinders are hard on batteries and one of the main reasons mirrorless cameras get far fewer shots per charge, but also give a helpful preview of how an image will look with the current exposure settings and can display other useful info such as electronic levels, histograms, manual focus assist features and more.

Some possible DSLRs:

D7200 (used)... DX, 24MP, best image quality of any Nikon crop sensor camera. Around $700 used.
D500 (used or new)... 21MP, most pro-quality DX camera Nikon makes, on sale now for $1500 new.
D7500 (used or new)... DX, 21MP, sort semi-pro camera next to the D500. $1000 new.

D750 (used or new).... FX, 24MP, popular model that's only recently been superseded by D780. D750 on sale now for $1500 new. D780, $2300 new.
D850 (used or new).... FX, 46MP, a popular semi-pro full frame model. $3000 new.
D610 (used or new).... FX, 24MP, a more affordable, entry-level full frame model. $1000 new.

Some possible mirrorless:

Z50.... DX format, 21MP, on sale now under $900 new. Two Z-mount DX lenses so far (but F-mount w/adapter & other Z-mount can be used on it).

Z5, Z6, Z7... FX format, earliest models, 24MP to 46MP, on sale now for $1300 to $2500 new.
Z6 II, Z7 II... FX format, newest models, 24MP and 46MP, $2000 and $3000 respectively.

larryepage Loc: North Texas area

Somewhere along the way here we have "lost the fox" and moved to standard UHH pontification mode. The OP clearly stated in his original post that he was not interested in sending anywhere close to even $2000.

CHG_CANON Loc: the Windy City

If you hear a voice saying, 'Your photography will get better with a better camera,' just mute the speakers on your computer.

lsupremo Loc: Palm Desert, CA

Don't you Nikon Z types understand the word BUDGET!!!

SuperflyTNT Loc: Manassas VA

The Z50 with 2 excellent kit lenses and FTZ adapter is well within his budget.

augieg27 Loc: Central California

Nikon D5600 or D7200