What do you mean with subscriptions? Are you paying regularly for something?
In-App purchases handled by the Play Store are tricky to work around, if the App in question wouldn’t offer alternative payment methods.
If you paid for installing OsmAnd+ (since you mention it), this is not a problem. OsmAnd+ is available as OsmAnd~ (the tilde is important) free of charge in the /e/OS Apps installer (and in the Open Source App Store F-Droid, where the Apps installer gets it from).
Most cost-free Apps from the Play Store are available in the /e/OS Apps installer.
There’s also an Open Source client to access the Play Store directly - Aurora Store (also available in the /e/OS Apps installer). Aurora Store uses an anonymous account by default, but you can also use your own Google account with it to get access to Apps you paid for in the Play Store.
Keep in mind that most Apps in the Play Store are dependent on underlying Google services in the OS, and while /e/OS has microG in place as a replacement for those, it is not guaranteed that Google-dependent Apps will work with /e/OS 100% all the time, or at all. Many Apps just work without a problem, though.
Perhaps search the forum first for mentions of Apps you find most important, also mind [LIST] Banking Apps that work on /e/OS.