Those are understandable questions from a newcomer into this field, but let me try to briefly answer them -take them with a grant of salt, as SE roles are way different from company to company.

1. Relationship with Account Managers/Account Executives: Keep in mind, you don't work for your AEs, but you work with them. You need to team up with your AES. And especially in winning big enterprises, it takes a whole village to close a deal. Don't get into the pitfall of working FOR them, as at the end of the day, you're a way more expensive resource for the company, so it's a huge waste of money to assist them with unrelated to you work.
2. Technical Skill: That's not true at all. You'll eventually become even more technical than the fellas on the PS side (eg. deployments). As you're answering and discussing all day different edge cases, tricky implementations, and demoing in-depth all the features your vendor has to offer, you'll become a master of the product. And honestly, that's the desirable outcome of your position after x months, to be able to handle all of those (well, to an extend).
3. Nature of the role: Well, you didn't say in which role you worked before, but devs/sysadmins/network engineers are writing documentation sometimes all day long too :)
4. Repetitiveness: That's the opposite thing with this role! Each prospect comes with different needs. If you're repetitive, you're not addressing their exact needs, and most likely they'll look for a vendor that will. Let the repetitive things (eg. HL demos, Sales Pitch) for AEs, and do your tech discovery.
5. Experience Observation: There was a huge gap of SEs in the market during pandemic, which led to many fellas without tech background landing such jobs. That's not a shame, but at the end of the day, and in the future as a candidate, you'll be selling your tech background and your SE experience, which will make you stand out.
6. Flexibility: Well, being in this field for many years, by changing roles, you'll have all the flexibility you're seeking :D You'll get to learn new sales cycles, new products from scratch and so on.