A few countries now have remote work visas (Spain definitely, Portugal too I think). As long as you make good money (any software engineer salary is fine) and it comes from abroad, that'll work to get you in the door. Alternatively you can find an big international company (who will often work in English) with a local office.

In Western Europe at least, English-only in day to day life will be a moderate challenge but not a critical one (many people speak at least basic English, you get good at pointing effectively, you learn essentials much faster than you think), you'll find people & services targeted at expats to solve exactly this problem, you meet many many other foreigners in the same situation, and with a little time you really can learn a language even if you've never done it before (and doing so is genuinely an interesting and meaningful project that many people enjoy).

I moved to Spain with no Spanish. First year or so is tricky but manageable and definitely not boring, and then from there on it's relatively smooth sailing. Quite a few years later now, worked out great, best decision I ever made.