Coming from the opposite end of the beta discussion: I am very proud of my skills in spelling, grammar, and punctuation. However, three fic writers have asked me to beta read for them in the past, focusing on these points specifically, and each one has- upon seeing my review notes for the aforementioned- replied immediately with things such as, "that's just my writing style," "how did I miss that one misspelled word? I'm so stupid," and similar.
I've tried to adapt. I read the things they posted before they'd asked for my input. I balanced what was perceived as criticism with praise. Sometimes I even outweighed the former in favor of the latter. But they always inevitably cried, or got defensive, and quickly stopped asking me to beta.
So, anyway. I don't know if it's because of how I do things (brief, to-the-point notes seeming cold, maybe?) or if I just keep encountering people who are so sensitive to rejection that any small mistake being pointed out is taken as an insult to the writer themself.
I love beta reading. I'm proud of my ability to do so. And it's the closest one can get to being an editor anymore, since job opportunities for that are rare to nonexistent. But no longer feel secure putting myself out there and volunteering to do so. And I genuinely wonder how many others have gone through this, and if maybe that's why beta readers are so hard to come by?
Hi anon. *hugs* I'm sorry that you haven't found a good match with an author yet, especially if editing is something you love and miss doing. It's heartbreaking when you have something you want to share and you can't - and that includes the skills you mention here.
I think what others have said can help - having conversations before, during, and after beta reading to set expectations and try to be on the same page (no pun intended).
But I also think that sometimes people don't know themselves as well as they think they do. I have definitely said I wanted Thing A before when it turned out what I actually wanted was Thing E instead - and I had to go through A-D to figure that out.
Your way of editing is probably a dream for some folks and a nightmare for others. If I were the kind of person who could wait more than 5 seconds before posting a chapter, I'd probably want a beta like you.
One way that might make it easier to find where you and the author can meet in the middle would be for you to do a sample paragraph or page of beta editing for a work that neither of you have written. Without the personal element of the author feeling protective or sensitive about their work, you can demonstrate the kinds of comments you tend to leave and they could provide a version of those comments that aligns with what they're hoping to receive on their own work.
I'm thinking something along the lines of:
You: This is a run-on sentence. You can correct it by separating it into three sentences here, here, and here or you can use a semicolon here and em-dashes there.
Them: This is a run-on sentence. Grammatically we could fix it, but you could also leave it in as a stylistic choice. It changes the pacing of this scene into something more frenetic and breathless. Is that what you're aiming for here?
Obviously this is a totally made up thing I'm doing here, but this is also a mismatch that you could identify early. If you're not comfortable making the kind of comments that the author comes back to you with, then you're probably not a good fit for each other.
Betas like you are a lifeline for a lot of authors, and I hope that you can find one that is looking for your style someday š