From a personal perspective: What I've learned about free markets is, that you can usually find a match with every customer who agrees to accept what you offer. So if you apply to a senior position and someone accepts you as a match, there you go. We as a global industry don't really have an standard for career paths. At least I personally don't know any. Whereas being accepted as a senior, but only having 1 year of industry experience might be pretty rare though. So expect a correlation with documented years of experience though.
From what I learned in the European market is: Senior roles are expected to be able to independently reach quality results without too much extra attention/help from their direct management or technical team leaders. If you've been the sole developer for a long time in your space, chances are good, that you are already showing this capability. Even though when changing from a small/mid startup to an enterprise company this might change in a sudden, because now you are in a total different problem space an culture. Boundaries seem a bit fluent or fuzzy here from my personal POV.
On an extra many companies seem to categorize personal into senior tier, when then additionally are able to hand down the torch on knowledge down to the more junior levels, to enable them doing their work better than before.
Source: Working in tech since 2000, 10 years of dev/arch consulting with different companies, right now software architect in a starting to scale mid size organisation, mentoring juniors and seniors.
Hope it helps. Wish you all the best.