This is going to sound mean and preaching, but it is not meant to be. Think of a parent giving his child a stern talk after it did something stupid

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[...] only gathered 20 blueprints [...]
[...] I feel like it's hard to log in suddenly [...]
You "only" gathered 20 blueprints? There is
no activity in-game that required you to get 20 blueprints at once. You decided to grind because you wanted it all at once. What you are feeling is the well deserved burnout after needlessly grinding because either some guide said to do so, or because you were greedy.
The best advice to give is: Take a break for now until it itches you to go back to the game. And avoid those one-stop-grab-all grind sessions in the future.
There are people here who mock the "just play the game" advice, but it is the best one to give. I have done many, many guardian sites for blueprints; let me count: I unlocked the FSD booster, Guardian MRP, HRP, PD, shield booster and Power Plant, and one fighter, small and medium fixed Gauss Cannons and Shard Cannons, and four Salvation Plasma Chargers and Shard Cannons. That's all stuff I can remember I needed blueprints and guardian materials for, and that makes 19 blueprints I collected from guardian sites. Maybe there are more, I don't remember.
But of course I didn't collect them all at once, why would I? I would never have needed them all at once. And neither do you, probably. The FSD booster is almost mandatory, but the other guardian modules are optional to useless (the MRPs and HRPs are nice-ish, the PD and PP are kind of useless an were probably a waste).
I did all my unlocks over time not exactly when I needed them, but when I thought it was a good idea to do so. The first one of course was the guardian FSD booster, and once you got that and a somewhat proper build, it's a matter of a single two hour play session to jump over to guardian space, collect one, two or a handful blueprints and the necessary materials, and jump back. That's hardly a grind.
What you did was crush your soul voluntarily. If you learned that lesson, there is no need to redeem yourself, the burnt out feeling is punishment enough

. So take a break, and don't do it again

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