If Sony ever wish to enter the portable market again, they need to rethink their strategy, the portable market is not about power, especially true when Steam Deck is out, there is no reason to compete with it in terms of raw power.
What they should do is releasing a device that is affordable, good battery life, convenience such output to TV, but what's most important is SOFTWARE, they need to design software specifically targeting portable habits, people play game differently and likes different types of game when on the go, games like Animal Crossing, Minecraft, Monster hunters, Stardew Valley are killer app for this kind of habit, these software doesn't have to be triple A, in fact they are actually cheap to make, the low budget of these titles will enable creativity since even if it failed they could always try something new, this route also has the benefit of not dividing too much resources from their Home console line, which will ensure their console games are still the same quality. Most Sony studios does not lack creative minds, they are totally capable of creating games that are cheap to make but fun to play, and since these software are exclusive to their device will enable the desires to buy the device just to try something new.
Of course making something new doesn't mean they can't just port some of their previous gen home console line up to the device, but their main focus should head to creativity where they could experiment with all sorts of stuff
The short history of video game industry told us, handheld is never about raw power, every handheld that pursue raw power mostly end up failing.
For those of people that think a handheld is a bad idea, its only a bad idea when its poorly executed. The real bad idea is to copy everything Microsoft does, Sony cannot out buy Microsoft in terms of studio, their market caps are lopsided in favor of MS, the odds are also not with Sony when it comes to subscription service. They should create their own route and co-exist with different area of expertise, but unfortunately that is not the current direction they are heading.