Other users solve that by using a generic battery …
Other users solve that by using the Android 4.4 alpha …
These are no long term solutions, and there are of course also good reasons against employing the both of them, but if you perhaps just want to buy a bit more time to decide, these could help .
About your pros and cons …
Understandable, but I’m honestly curious now about which phone you want to buy if you would have to buy it right now in this moment.
Android 8 is more unlikely than Android 7 already was.
But software support also encompasses regular delivery of security updates. Fairphone absolutely deliver in that regard up until now, not many vendors do the same.
If you prioritize the sole Android version number over that, I guess you are not in the target group.
Your call. Nobody here has a way of knowing just now (probably).
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