Wow, that’s a huge number. I assume you know there’s no quick and easy method to convert these formats to digital – it’s a real-time, one-at-a-time proposition. Hope you have perhaps years to do all this (assuming you aren’t retired).
If you get an audio interface and an audio editing program like Audacity you should be able to record straight to your computer. You’ll need a phono pre-amp for the TT.
I got a head start by replacing any LPs or cassettes that I cared about with CDs. For the ones I couldn’t find on CD, I bought a ’90s vintage Pioneer CD recorder on ebay, along with some music CD/RW discs that I could re-use. Then I recorded the LP / cassettes to the Pioneer. The beauty of this method was the assurance that the Pioneer had excellent A/D converters to insure the best sound quality, and it could be done without tying up my computer, which I could use for other purposes while the discs were recording. The discs could then be ripped to my computer, and then cleaned-up in Audacity.
Regards,
Wayne A. Pflughaupt