The 4a was pretty sweet. I think it had a Snapdragon 7 series chip which was not the fastest but not slow either. I would think that the Tensor G2 is a lot faster and the GPU in it is decent. The Tensor G2 is a lot faster than 7 gen 1. So it is still an upgrade over the 4a and that is saying nothing for AI chops.I had the 4a and I thought that phone was great.
Every now and then it had a hesitation but it had a lessor GPU chip. Fingerprint sensor was super fast and accurate and loved it on the back as opposed to in the screen.
If I didn't have the P7 I'd absolutely get a 7a since it has wireless charging now and the G2 chip.
FP sensor in this P7 is trash. ....but I don't care. I just use face unlock. Also not sure if it's just my phone but Dailey Mail app for instance, always freezes on the P7. Also a car forum I go to,.... it freezes up as well and restarts the phone on its own. Didn't ever happen on my 4a.
I can go on certain websites as well on my Samsung s23 Ultra and get freezes. It happens worse on my Pixel 7 Pro but my point is certain websites can cripple the best CPU.
Considering your particular experience with the 7 the 7a would probably be a better choice but if you really don't like the Tensor G2 (which I can understand) I don't think the 7a would offer a much better experience. It is pretty much the same phone in a different package.
I think the Tensor G2 is a pretty decent chip on par with SD 8 gen 1 with one caveat. It needs to have a decent vapor chamber cooling system because it will heat up. Google should have implemented better cooling but I think they thought by underclocking the x1 cores would be enough and it wasn't. Thermal throttling is the biggest draw back to the chip and it could have been mitigated with a proper cooling system.