How heavy/tall is your DD? Most intereted in a seated height to top of the head (or just measure how many inches she has before the top of her head reaches the top of the shell in her seat). Is the seat you have the Triumph Advance (30lbsRF/47lbsFF with infinite adjust harness - has red tabs over shoulders) or an older Triumph (I think that harness had slots for diff harness heights)? The Advance ("EFTA") has a nice tall shell while the older Triumph I think was not as long-lasting. We recommend to RF until at least 2yo, but preferably to 3-4yo. It is totally doable with the seats on the market now!
What is your other vehicle?
Re: hating the car - is your seat installed at a 45 degree angle still? An older baby with better head control can gradually be installed more upright and many prefer to be more upright so they can look around more, so that might be something to try. Some EFTAs also had issues with a bump at the lower end of the harness adjustment range that would press on baby's back, so this could be the issue as well. A different seat might help. Another issue with the EFTAs can also be that the knobs allow the harness to be over-tightened, so make sure that the harness isn't squeezing her. You want to tighten just until you can't pinch any slack across the strap at the collar bone, but not so much that the child "re-inflates" when you loosen it a bit.
Radians are a wonderful seat and they will last the longest both RF and FF, but do at times have install issues, and also it is hard to adjust the angle at which they install, so if you can't install it upright enough for your older baby they do take up a ton of room front to back. They are definitely worth a try, though!
The Britax seats are fine, they do not last quite as long as some others and have less leg room for RF than other seats, and also tend to be expensive compared to the competition, but are very nice seats none the less. They do fit small spaces, for sure. I would consider other options as well, though.
Depending on weight/height, I would also consider the Graco MyRide, the First Years True Fit and the Safety 1st Complete Air. All will fit in a smaller vehicle quite well, even the TF and CA with their very tall shells, because they easily install more upright. The TF and MR will fit a small baby well, though if you needed a seat for a new baby you could always use the EFTA for the baby and use the higher-RF-wt limit seat for your DD.
The EFTA that you have is a good seat but these days a 30lb RF limit is really too low for all but the most petite children to ERF, so I would not buy another Evenflo convertible.
Another very budget friendly option which has decent RF limits and will fit a smaller baby, and fits very well in small spaces, is the Cosco Scenera. It is very bare bones but perfectly adequate. It also has it's new cousin, the Safety 1st OnSide Air, which is a bit more but has the "airbags" and maybe better padding.
Hope that gives you a start to ask more details about the seats you are interesed in. I would pick 2-3 front runners and then go to the store to try DD in them, and do a trial instal to see how they fit.