Yes... Agent is both a purveyor of a program which downloads articles/files, but also acts as a middleman for hosting the files. You pay a one time fee for owning the software, then a monthly fee for access You choose the level. I NEVER use more than about 5-6 gigs, though you might, since you have special interests.

"A long time ago" usually means over 200 days or so... and you 'can' get some stuff at 900-1000 days.

Once Agent is installed and properly configured, you need to
'subscribe' to groups you wish (which simply means make a list of your favorites)....you would begin with those groups where you already found interesting stuff, but from their list of 100,000 groups, you can explore dozens of categories. (Somewhere I found lists of the largest, most active groups...which is a sort of guide helping to avoid inactive groups.)

IF you go ahead and start this, I'll try to show you the ropes of navigating thru the messages (been at it for about 15 years now).....Agent has SO many tricks that it takes awhile to use everything. (Wait till you get to .nzb files! *grin*) (or, you can look up online guides...there are always pages of 'expert' help.