First - good powering and grounding is very important and your basic approach is solid. A filter matters ( i have no opinion on that particular brand and made my own which is awesome) and a single place where they are all grounded to ( a big, good power strip or several connected to one outlet) is a great start. The dedicated outlet too is good.
Well, I’ll take the dissenting opinion on upgrading power cords, not just theoretically - but i’ve swapped a bunch of cables. IMO, its at best "way down the priority list". This may have to do with my power (ok) and my equipment (really good power supplies everywhere). But to a degree that’s my point - get the basics right and no magic cables will be required. 60 Hz AC is just not hard to move about for a few feet, with a couple amps.
You ask about wall warts. Good question. 99% of those are switching power supplies. They suck in two ways: 1 they deliver very noisy power that must be filtered very well (not easy trust me). 2 They back feed noise into your power. You are creating exactly what you filter is intended to remove, but with A PROBLEM>>>>> its on the "clean" side of your filter.
To the degree that you can move those wall warts, TVs, computers, Roon Cores, etc to another circuit, do so. Most will have ground broken before they meet your hifi anyway (TV via toslink, Roon visa ethernet). I put my core in another ROOM.
Next, and this may be overkill, if they must remain, replace those cheap ass ($8) switching supplies with linear supplies ($200+, sorry, that’s way they exist). If there’s no ground connection and they are remote, maybe don’t worry too much. But at minimum plug them in on the other side of your filter. I use one filter simply to block the back feed from digital crap. Note my commercial designs have their very own isolated digital junk transformer. Its costly, complex and necessary. And makes awful advertising copy.
I do use an isolation transformer. You need, amplifier depending, about 1kW to be comfy. Most filter similarly. Many are mechanically noisy. Mine is medical surplus, mounted remotely near my panel, driving the 20A feed.
G