Also you’re in the EU so could feasibly move to where needs your exact skill set. But web/frontend/backend is needed everywhere so it’s likely worth adding that to your C skills.
You _could_, but reaslitically speaking the frictions with language, culture, and distance from family and friends probably makes this harder than maoving US -> Canada or vice-versa. The EU tried hard to overcome this, but they're fighting national differences and cultural borders older than Christianity.
Don't lie about anything in your resume/CV. If you get called out, your whole reputation and your whole CV then is in Question.
Not sure if it is same in the EU, but if it is illegal don't volunteer your age. No need to lie.
But perhaps you can be economical with facts and/or 're-prioritize' them, if expedient, ie choose which cards to reveal and with what emphasis.
Personally, I just tell it matter-of-fact as I see it, pretty much. You're looking for a good match of a job after all so may as well be fairly honest. Take that advice with a bucket of salt though because I'm still looking after <cough>, a year ... <cough, cough> ... or so.
Uprooting your life when you are 25-30 is easier, can be a fun adventure, etc. Doing that when you are 50 is many layers more complicated.
Lying is absolutely a no-no, there's no upside, you will be forever in debt about a lie and in the case of something as easily detected as your age you will lose all credibility for a stupid reason.
Asking someone to move is usually quite unreasonable, unless there's legit problems where the person lives. A lot of people, especially people in their 50s, have roots that they just can't walk away from.
Furthermore, software gigs tend to be much shorter than how often people stay in a location; and remote work in software is super-common today.
Padding the resume isn't a bad idea. If you've worked in C, and taught yourself Go, you're senior in my book. I mean, you may not know the gnarly corners of the language and eco system, but that's easy enough to pick up.