I have a Steam Deck and a PC I use for gaming. For me, the deck only gets used if I'm going to stay elsewhere for some time, or if I can't access my PC, like when I had surgery and was in bed for about two months. But under normal circumstances with PC access, it rarely gets used and is currently in mint condition. You should ask yourself if you'd actually game "on the go". Personally, I can't imagine using it for a commute that lasts an hour or so, but something like a long flight makes sense if it's frequent. I don't believe in taking it along on trips either, because that defeats the purpose of a vacation for me, unless I'm alone and know I'll have plenty of free time where I won't venture out.
Enough digressing. If you've made up your mind to get a handheld gaming device, then consider your platform usage as well. If you already have a Steam library or have a few games in mind you're willing to buy, then a Steam Deck OLED (Or even LCD) is great. If you don't, then I'd say a Windows device like an Ally, combined with PC Game Pass, would be a great combination. I know you could sideload Windows on a deck, but that's an unnecessary hassle unless you're someone who feels immense joy in tinkering and configuring things.
Also, if you think you just want to lie down at home and play, what about a PS Portal? Admittedly, I don't know much about it, but considering you have a PS5, you could stick with the same platform, but with a form factor that's convenient for your use case.
