At least get your orders of magnitude sorted out. 700MB is how much data a CD can hold, so either you're using alien technology to stream your 4K or you meant GB and not MB.
Which, you must be all watching one thing and do nothing else. When it was just me and one other person and us streaming at 720p and some game downloads, we'd use 300-500GB a month on 15-20Mb down (we moved to cable after ATT DSL was trying to charge us $30 extra per month for going over their 150GB cap, streaming 480p and less quality). If you have a modern family of 4-5, with one person working from home and one or more children doing distance learning, on top of say 3 unique 5 hour daily 1080p streaming of TV/movies, you're gonna be hitting probably 1TB+ pretty easy.
If you have one IT or software development person working from home, and a family of 4-5 doing 4K streaming for 4-5 hours a day, one person gaming while Twitch streaming, etc, you can easily hit several TB. Especially if you buy a new PC or console and have to download several 100GB+ games.