I have a MYFI device aka mobile hotspot device for internet use. Where I live I get 1-2 signal bars on a good day. 4-5gb download takes 1-3hrs to complete. When downloading large games I sometimes lose the connection causing the data that was downloading to become corrupted. Which means I have to redownload the data again. I don’t like combining game downloads because if the new version has had any software updates in it then when trying to combine with older version can cause game errors causing me to have to redownload the whole game over again. I have had this problem a few times in the past. I use a laptop I bought from a pawnshop just for downloading and playing these games from itchio and F95zone. The laptop has never had any of my personal info or accounts used on it. I use a few USB storage devices ( My Passport and Toshiba) that have 2-5 terabytes of storage for each device. I got these from a pawnshop for $25-$40 each. For the device I plan to use on my personal Computer and Laptop I drop them off at a computer repair shop and had them cleaned and scanned for viruses cost no more than $40 and it’s still cheaper than buying them new from a retail chain. You can always leave your contact info at your local pawnshop so when they get the item you want they can call or email you. I have done this for many items and multiple places.
Sounds like you're just gonna have to gamble and hope it downloads the whole thing. I found that babysitting the download sometimes works. Or deal with an emulator I guess, but that tends to have buggy controls because it's assuming you're using a phone and not a PC/Laptop.
My recommendation is to just check on it periodically and if it's stopped, hit resume. My current internet also bugs out and breaks the download and it occasionally works again if I hit resume. Sometimes it'll get corrupted and say the download is "forbidden", sometimes it won't and it'll actually start downloading again.