Robin, what you are planning is definitely doable. I am 68, have been traveling by myself for almost 30 years and consider myself a budget traveler. That said, my budget has definitely gone up over the years. However, I still hunt vigorously for hotels and B&Bs that are low cost but comfortable. It can be done. You just have to spend time looking.
And as others have pointed out, your budget will be forced to change depending on the country you visit. Places like the UK and Scandinavia are very expensive. Places in Eastern Europe are much cheaper. I'm planning a 5 week trip to England next year, and spending more per night than I usually do, but still have managed to find places that are inexpensive and under. It just takes research and due diligence.
Also keep in mind that cities are generally much more expensive than smaller towns, especially the less touristed ones. So you could easily stay in a small town and plan on using inexpensive public transport to get to sights and places you want to visit.
With regards to cultural barriers, you might want to start off easy and head to a place like the Netherlands, where just about everyone speaks English and the cultural "barriers" are very low. You could stay in one of the smaller towns outside Amsterdam and use public transportation, which is excellent in the Netherlands. Start off with a short trip - 2 weeks or less - and keep your itinerary simple, as you said.
And regarding all the minor stuff - visas, power banks, etc.; focus on the big stuff first, like choosing a destination, figuring out your itinerary and then moving on to a packing list and so on. The only country in Europe that I know of that requires a visa, by the way, is Turkey, so you probably won't need to worry about that.
Once you are ready for the 'small stuff,' head back here and you will find a barrage of members who will help you plan your packing, sort out chargers and adaptors, and help you with cell phone usage while traveling. We all LOVE to travel and more than that, we love encouraging and helping others to do the same thing. So please do not hesitate to come back here with as many questions as you like as you do your initial research. 😊