I have a work place, stuff taking a detour and paying someone to hold onto stuff for me. 2 HDDs, one sitting in my desk drawer at work. Each Monday night I plug my backup in, and on Tuesday I take it to work and bring the other one back. I plug it in and an automatic script backs up my NAS and emails me the results.
You don't forget routine. If you're forgetful, make something a routine. The easiest way to do that is tie it to an existing routine like something you do on the specific day of the week, or set a reminder in your outlook calendar. That's why I pick Tuesday. I'm incredibly forgetful so I tie my backup together with preparing my sports back Monday night. Tuesday is Squash day, so I have to take an extra bag to work, which makes it easy to run down the list: towel, racket, pants, shirt, shoes, socks, 8TB HDD. I mean you don't really consider your data important if you're forgetful enough not to back it up right?
The point of these online backup services is that they serve a purpose for a select subset of use cases. Small data sets are perfect for this. That precludes it's usefulness if you're into photography or worse recording videos. They are also great right up until you have an actual failure and your background backup operation suddenly becomes an excruciatingly slow foreground operation.
Also while I have quite a bit of faith in Backblaze and I'm quite a fan of their work, the same is not universal around Cloud storage providers, the ones who a notorious at offering you a service, oh wait we'll change the price, oh wait you now have a limit, or now there's a bandwidth limit, oh we got acquired by someone you have 5 days to suck your data off before we delete it all for you. Once bitten....