Which PC power supply is ideal for me?

I would like to set up a dual PC system and am currently looking for a suitable power supply unit. One system should be rather small and economical, e.g. To use it for surfing or running a small Minecraft server (so it can also run on the side or alone).

The other comes later on the one hand and should on the other hand be intended for gaming with a higher energy requirement. I'm thinking about a correspondingly large power supply, because I calculate 200W for the small and approx. 600W for the large system (with max. RTX 3090 etc.). The problem now is that I can only install one power supply in my Phanteks Enthoo 719 and the requirements conflict. I have the following power supplies in mind at the moment:

1) Phanteks Revolt X 80 PLUS Platinum 1000 W (designed for dual systems)

2) SeaSonic PRIME TX 1000 W 80+ Titanium (I would have to build an adapter to use it for a dual system)

3) be quiet! Pure Power 11 400 W 80+ Gold (would later be replaced by 1 or 2)

For a while, I can imagine option 3, but would have to replace it if I want to set up my gaming system. Option 1 would be well suited for a dual system, as it already has the appropriate connections. But it would "only" be platinum and thus the efficiency might not be as good if I only run the small system. Option 2 would not be bad here, because from 10% load an efficiency of 90% (but of course more expensive and not intended for dual systems).

I'm aware that in my case it might make more sense to operate the systems in separate housings, but somehow such a dual system appeals to me (clearly actually intended for streaming or simultaneous operation). Do you see other options or suitable power supplies that would suit me or which power supply would you choose? Of course, option 2 in particular is very expensive, but it would be worth the investment to me. Otherwise I also thought of option 2 but with "only" 750W but it could get tight at some point if I really want to realize everything.

But it would "only" be platinum and thus the efficiency might not be as good

You can completely neglect that.

At first I'm critical of such adapters. If there's a device that is intended for precisely this purpose anyway, why not use it right away?

My thought was that the SeaSonic should have the better efficiency even at 10%. And as an electrician, I have the confidence to build adapters. The problem with the X is that it is not 100% intended for my application, because Phantek certainly thought that both systems would run at the same time.

Here you have some test data to compare:

http://members.cybenetics.report:5050/d/cybenetics_7md.pdf

http://members.cybenetics.report:5050/d/cybenetics_tmD.pdf

If you look into the low load range around 50W, there's no 5% between the two. As far as I've read, the Revolt X has the Seasonic Prime Platinum as its base, so you can compare the 1: 1.

Thank you very much, I wasn't aware of that. The Revolt X is of course the best choice (especially because it is probably cheaper).