First impressions (all on desktop, not mobile):
On the individual mod page, things look pretty decent except for the title font, which is too wide and a bit ugly. The old font being slim had many advantages, including being able to show longer titles. Inter is too much like Helvetica/Arial in all the wrong ways. Switch to something slimmer. It doesn't have to be Bebas Neue like before (although that font was great), but it's just way too wide right now. Otherwise I don't really have any big problems with it.
The page where I browse mods, however, is terrible. The experience is a massive downgrade. For reference, I view mods in the last-updated order by default.
Here are the bad parts, the main theme of which is WASTED SCREEN REAL ESTATE, especially in the vertical dimension.
The header at the top of the page is completely wasted space. It should be vertically slim, no more than 30px high. The new header is 124px including padding, which is way too much. Nobody needs this.
The new listings for the mods are too big. I used to be able to see 2 rows of mods per scroll; now I can only see 1 1/2. This is unacceptable, and results mainly from the following:
Vertical padding in the entire block below the mod image is excessive. It's 0.75rem on top and 1.25rem on the bottom, but it should be 0.5rem for both.
Too much padding is below the author. 0.5rem should be reduced to 0.2.
The individual sections for mod category, updated/uploaded, have more excessive padding. Again this should be dropped from 0.5rem to 0.2.
The mod title is too large. 1.125rem is too big; 1rem is better.
The line-height of the description at 1.5 is nice and readable, but wastes too much space; the standard 1.2 is inadequate. A compromise of 1.35 buys back some space. This also helps with the mod title when it wraps to more than one line.
Despite all I've said above, a limit of 4 lines for description text is often inadequate; change the -webkit-line-clamp to 5 instead of 4. It does undo some of the vertical space saving, but it's important.
Nuke the min-height on the mod listing. It's currently set to 28rem. Without it, a small amount of precious space is recovered.
The very bottom line with the endorsements/downloads/size has a min-height of 2rem which is wasting more space. 1.35rem is much cleaner.
There's too much spacing between grid rows. The column spacing is fine, but the excessive row gap wastes vertical space. 2.5rem is absolutely insane; drop it down to 1rem and no one's going to mind.
(Enacting all of the above changes gets me nearly back to 2 rows per scroll. I can live with nearly.)
Right below the top page header, there's a ridiculous amount of vertical padding on the filter column and the main results area. Reduce it from 1.5rem down to 0.5rem, which is all anyone needs. 1rem if you must.
Below the sort options at the top, there's even more useless padding.
"Some mods may be hidden based on your content blocking settings" appears below the result count and the sort options. This is wasting more space. Put it in between the result count and the sort options, where you have a ton of empty space.
At the bottom, there's a gigantic margin below the grid, before the pagination section. 2.5rem is too much. However, I do kinda think 1rem is too little. 1.5rem seems just right.
The last-updated time for each mod doesn't show a date; it shows "<time> ago". As nice as that is in some ways, it's useless if I'm trying to see all mods that updated since a specific day. The only way to tell is to mouse over it, which isn't great. I can live with this but I'd prefer some customization or something.
So that's the bad. Let's go over the good:
Despite the loss of more vertical space it entails, I do like the larger images. Despite my massive concerns about vertical space, I think you can get even better results by dropping the grid column gap from 2rem to 1.5rem, which only costs a couple of vertical pixels.
The filters being on the side are really nice. It's intuitive. I like that hiding them presents even more mods per row.
Bottom line: Treat vertical space like gold and expend it wisely. Right now it creates a severely downgraded experience.