Sometimes they take a while to load but recently there was issues after a cyber attack on the servers so perhaps this issue could be a result of that. Best thing to do is use the in-game feedback option to send a bug report to the devs, it automatically attaches your logs with everything they need to help fix the issue.
For some reason while blueprints are perfectly visible in the ingame store, there's no access to them either from Adventure or Editor. Both modes show empty blueprint folder, while there are actually plenty of blueprints, and some were spawned ingame before, both while 2.3 and 2.4. Happens both to new blueprints and existing ones.
Check your savegame folder for Steam and see if they are still there. The location is C:\Program Files (x86)\Steam\userdata\ <steamid> \298610\remote\SaveGames
Also, now that you can get into the game, send the developers a bug report via the in-game feedback option in the pause menu or from the settings menu. They will be able to help you better with your log files.
