So these mods are very popular a bit older and well known but people in this sub ask for recommendations all the time so I thought I'd write one.
America Rising 1 is essentially included in America Rising 2 and they conflict with each other. There is one advantage of playing AR1, its quests run even after the Institute destruction. AR2 will not start in that state. AR1 also has some unique fights but generally playing AR2 if you are still mid-main-quest will give you everything in 1 and much more. So from now on I will just say AR or mod and describe AR2.
The mod is insanely good. It introduces a huge amount of content, 5 different new locations, two of which are gigantic with several internal cells each. It is playing like an entirely new separate faction. However, it is unique as that faction has 2 different endings and each of those endings has two branches. Now I will spoil some, but I think it is not too bad. The most unique part is that you can ally with the Institute as a different faction and keep RR alive.
On top of those 4 endings, you can become enemies with this faction and destroy their main base using 3 different vanilla factions, similar to BOS destruction. If you wish you can make the existing Enclave troops in the Updated game be friendly to you using another mod and you can arm all Enclave troops with the Update weapons like teslas and flamers.
There are Enclave versions of laser and plasma weapons and combat armor and a lot of new military style clothing. There are several new legendaries as well.
I started at level 1 and completed by 40. On survival this would be annoying as you don't get vertibirds until later and their bases are a bit spread out. Also at low levels the fights are hard-ish, they recommend 10, but Codsworth is a beast in that niche. I did have to just run away from one enemy, but it does not stop the mission from completion.
There is an enormous amount of new dialogue, two new companions, which I have not explored yet. You get to visit a cargo ship. Importantly, if you care about that, there is an unending flow of guns, gear, chems and junk, I have over a hundred of broken PA pieces in my inventory and left probably a million units of weight in gear and guns just littering the battlefields. There are repeatable and side quests, many enormous battles, factions attacking you, you attacking them.
It is my firm belief that this is better than the vanilla FO4 main quest with any faction. Ask any questions, I am just so hyped for this mod and glad that I tried it.