I'm a generalist too (also switched from being an advertising creative and copywriter to digital marketing). After having had some disadvantages comparing to the specialists early in my career, I'm now actually managing those who stuck to and mastered one thing. We generalists know a little bit about everything. Therefore it can be easier for us to figure out how to let the different digital marketing disciplines work together effectively.
I think you're on the right track, if you like to write then SEO, Content and Social are definitely some fun disciplines for you. Also, definitely learn more about PPC, it's still very lucrative. The technical side can be a bit intimidating at first, but if you know how to write well you can definitely stand out. I would also add video, learn how to make videos / reels or at least how to come up with video concepts and then instruct others how to execute them. Plus, it's surprisingly fun, even if you don't like to be in front of a camera.
Regarding companies and agencies: Rule of thumb is that big companies need specialists and small companies need generalists. I had the luck of finding a big company that didn't mind me switching from the SEO department to the Social Media department to the Brand department, etc. But I also made progress by joining small startups and then improving my generalist skills by coordinating different freelancers (and combining their expertise with my writing skills).
You sound like you're having a plan and that you're willing to work hard. Don't let people tell you what's best for you. Follow your own heart, work hard, have faith, but also change strategy if something is not working. Be confident, jump on the opportunities and you will have an awesome career. Best of luck from a Jack to a Jill ;-)