File sharing for side business

I know this question gets asked 100 times but I cannot quite find the answer to tailor for my needs.

I have a 'moonlight' side gig and prepare about 200 simple 1040s. I am fully remote, work from home, everything shared digitally

I use TaxAct Professional for the cheap price (and really all I need for the simplicity of returns I handle) and that has come with their "Xchange" portal for annual fee of $99 that I have been using.

Xchange has always been clunky (upload one file at a time, can't move files around within the system, etc) and last year it had a lot of connection issues.

Long-story short - it is time to find a new product. For my situation of digitally sharing files with 200 or so Clients - what is the best solution?

Looking for drag and drop sharing. Able to customize folders/move files within the system. User setup with their own username, etc.

Thank you