The T495 is s special kind of disappointment (I have one too), but the fault is with AMD. Zen 1 mobile has extremely aggressive C-States and they essentially never clock down. Ryzenadj helps a bit, but not much.

I have a P14s Gen 1 from work now, that’s one gen ahead but an entire different league in battery life (and it wouldn’t cook your fingers on the palm rest)

Newer kernels have helped a bit too, much more than TLP, if you still have that device try Fedora on it.

My experience too: until I got an X250 (i5, 2 core) earlier this year that lasts around 10 hrs on a charge. Cost $160 in mint condition. Noticeably less powerful than my old T430, but can still do some real work on the go. Screen and keyboard are seriously cramped though, so it gets uncomfortable over long stretches. Still, there's something to be said for small and light. My work laptop is a big heavy Dell workstation machine that could double as an offensive weapon in a pinch.

I've got an E470 with Ubuntu on it, no problems with battery life.