The cap goes up every round by a set number dictated by the mission, with the final turn being infinite supply- you get penalized via giving the enemy vp for leaving your dudes in reserves till the very end of the game without ever deploying them at all. .
Sure would be nice if their rules website wasn't shit, and when you hit the export PDF you just get a popup about the PDF functionality being in development. How do you fuck up the presentation of rules? Well they figured out how.
Marines and Lings are also not supply 2 as a unit by default, they are when you reinforce the squad with extra models. Both of those at their default sizes are supply 1.
Except they are supply 2. I don't care what their minimum value is, I want to know the maximum value. I don't answer how many guardsmen or ork boys go into a unit with "10" I answer with 10/20. So even with re-reading how the supply works, I'm still only starting the game with 4-5 units, I guess maybe 6 if I want to run min units for some reason. Even then after that I'm still only adding a unit at a time with the supply cap going from 6-8 or 8-10. This is fewer activations of units within a single round than some skirmish games.
The webapp has all the rules and data cards built in and is completely free if you want to poke around - I think the UI sucks still but i'm sure that could change in time
Yeah, it does suck. But when your game launches this is the thing players look at for information, it needs to not suck from the get-go. You only screenshot part of the page. This is what this stupid page actually looks like.

Why there's no part 1 in the menu? Who knows, but it looks dumb. You can't even hit enter in the search box and get a proper results page.
The difference here being if you get tabled in the first round somehow, you get to bring the rest of your army out immediately, because not only did the cap creep, your number of supply being in use dropped to 0 and can now be filled back to the new cap with what you have left in reserve.
Fine, the supply system is slightly less shit than my initial glance at it. It's still causing tiny amounts of units on the table. Being able to dump unlimited number of units from reserve in the last round is only meaningful if I haven't been having units getting killed off, which means I was already likely in a winning position to begin with. If you're playing on the backfoot you're likely going to have less available than the player who has been losing fewer units the whole time? That sounds awful. If there is a risk of getting tabled in the first round and it's not due to a fuck up on your own part, the game is shit if things can be decided that quickly regardless of reserves. Not even 40k has that without a player having 2 digit IQ.
Congratulations, I dislike this game even more now. It sounds even more awful in addition to the company being run by a piece of shit.