All your Canon EF/EF-S lenses will work 100% on any FF Canon mirrorless RF mount camera with the Canon adapter and the control ring adapter adds RF features to your EF lenses.
Canon has an excellent array of FF cameras from the R3 to the budget R8, which by the way has high reviews. If the R5 is desired I would wait for the MII in a couple of months. If super high MP isn't needed then the R6 MII is highly regarded with world leading AF, the latest hotshoe that will use all the accessories (The R5 doesn't have this shoe but the MII does. Or if budget is really an issue the R8 has the same MP as the R6 MII and the same amazing AF as the Canon flagship cameras have
It is lacking IBIS and has one card slot to keep the price down but quality of the end shots is right up there with the best.
Finally the Canon menu and controls will be what you are familiar with and you know the menus are regarded as class leading of any system.
And remember, all your current lenses will be great and can then be swapped out later if ever desired. I have only EF and EF-S lenses for my RF mount camera and so far see NO reason to swap them out. Also this way I can still use my EOS film cameras and DSLRs along with the RF camera and not have to have duplicate lenses in each mount. Who knows, you might want to do some film for whatever reason and ALL your lenses will still be there as they will work on all your cameras seamlessly.
Hope that this helps.
PM me for additional information and discussions as I have Canon and can advise from first hand experience and not just guessing.
Thank you

With all seriousness and not being an "a-hole" or wanting to burst the bubble, but my personal recommendation in photography is buy/replace stuffs only if the present gear could not achieve the idea.

Sure GAS is fine if one has the moolah, but IMHO, personal advancement or visiting places to shoot will always be better than new toys doing the same stuffs the old toys do.

But of course, that's just me. I do not know the full story on your side and changing gear might be the right move for you. Anyways, if that is really what you need, My suggestion is to know what you want it for, hence the choice would solve your dilemma. Borrow or rent if possible before fully jumping in.

Good luck and may you have bright lights and smiles, always.

That's a little bit of useful information. But, not enough. What specific body(s) are you shooting today? What lens(es) do you plan to continue to use on a full-frame mirrorless EOS camera? Other than spending some disposable cash, what do you intend to accomplish with this purchase?

Is a new camera that best thing to buy? What software are you using today? What speedlight do you own? What tripod? How is your computer set-up, especially the monitor for digital editing? Do you already have the best lenses? Do you have primarily full-frame lenses in preparation for a full-frame sensor?

The UHH community primarily thinks a new camera is the only way to improve. And, if you don't have the apex model of whatever line you shoot, you ain't nothing. They'll spend your money like their own. Don't fall into that trap if you don't have to ....