Don't struggle through a slow old Roku.
And, of course, I'm not really pitching Roku, if you've got another solution or want to switch companies, that's fine too. I'm just saying, anyone reading this who has a Roku a few generations back and having simply never thought about what to do about it, have a look at replacing it. Or any other streaming box that is generally choking. I remember getting into TiVos when they cost the modern equivalent of about $350-$400 and I still haven't fully internalized that streaming boxes can cost, well, more than "a coffee at starbucks" but at this point "less than a full meal for my family at a fast food joint".
They're not the cheapest thing out there, but you get a lot of muscle (and longevity) for your money.
Aside from that, having a little extra power available can be nice for being able to smoothly play back video formats that the hardware doesn’t have acceleration for, obviating need for transcoding (via Plex or similar).
On my WebOS TV's, AppleTV works exceptionally well, only Hulu and Netflix beat it in terms of reliability.
Paramount+ on the other hand. Total POS.