If you are a Canon Canada CPS platinum member you can do equipment test drives for 3-day periods, and they'll ship it out and back on their dime, IIRC. Otherwise, gold members are able to do equipment rentals.
CPS's rental list includes all the TS-E lenses and both TC sets. The new TS-E versions are $50 for the first day or over a weekend and $150/week. TCs are $25 first day/weekend and $75/week.
I'm not sure the RF TC will mate properly with the EF-RF adapter to allow use of the TS-E lenses. I seem to recall reading somewhere that the throat of the EF-RF adapter is too narrow to accommodate the protruding front element of the RF TCs (there are probably some old posts on this board, if you can find them). But I believe some have used third party EF-RF adapters to get around this. Otherwise you can definitely mount the EF TCs to the TS-E lenses and then use the EF-RF adapter.
I only have the first-generation TS-Es and also the 17mm. The 45 has a lot of CA, as you likely know. I have used the 24 v2 from time to time, but never tried it with the 2x. It might have less CA than the 45, but I doubt it will outperform it by much, especially shifted. I found that the 1.4x TC v2 on the 17 increased distortion unevenly across the frame, which might also affect the other TCs. I have briefly used the TS-E 50 and it was in an entirely other league in respect to image quality. Very sharp, great contrast, zero CA. It would definitely be the way to go, IMO, for best image quality. But of course it's the most expensive option. It's unfortunate to hear that it's very difficult to find and I believe the TS-E 135 has already been discontinued... On Canon Japan's equipment support page the 135 is listed as supported until 2027 (which confirms it has been discontinued), but all the other current TS-Es don't have end dates listed, meaning they haven't yet been discontinued.
It might be worth joining CPS at the gold level membership just for access to the rental pool. Plus you receive a 20% discount on servicing in case you have some gear that needs attention.
