Helldivers 2

I would put it this way. If you're the type of player who wants to unlock everything then you might be a bit late. But if you just want to have fun you can start at any time.

When it comes to unlocking everything most of the game is unlocked relatively quickly. Stratagems unlock pretty fast (I'd say maybe 30 hours to unlock all the stratagems, which is not a lot of time and most of them you might not even use) and have the biggest impact on your gameplay experience) followed by ship upgrades that also go relatively quick (maybe 60 hours if you don't shy away from difficulty 7) that just improve the stratagems.

But the thing that takes a lot of time are warbonds. Warbonds are essentially like battle passes except they don't expire. There are some useful things there, like weapons, grenades and armors, but they're mostly to give a bit more flavor to your gameplay and hardly a necessity. Those also take a lot medals to unlock everything. There's the free warbond that takes about 2k medals to unlock everything, but we also have 2 paid warbonds that each take ~600 medals to unlock everything and there's supposedly another one coming in 2 weeks which means we're soon talking about needing 4k medals to unlock everything. I have 120 hours in game and I have not unlocked everything in the warbonds. I imagine if you're going to start now and you want to absolutely unlock everything then you're going to need to grind something like 1k medals per month to catch up in 6 months.

Overall I'd say that the progression is logarithmic. You make the most progress at the start and then as time goes on your progression eventually tapers off into just farming medals and unlocking bonds.