Many thanks (!) to you both for this very helpful advice. So from what you both are saying/recommending, it sounds like it would be simpler not to switch to a business account.
I could indeed create a second account to continue adding notes, that sounds like a great idea for me to try - but would the existing account be seamlessly connected? That is/would be my practical and yes fairly specific concern, as PinkElephant notices perceptively. How do I ensure that I can continue to utilize all my existing notes too with no interruption. So for instance, if I add a tag that's already in the first account to a note in the hypothetical second account, would it be also automatically recognized and I could do an integrated search across the two accounts? And how would the second account appear on my desktop/local file? (I am using the legacy version, as the new version of the app is painfully slow and just does not serve the purpose for me.). I have many tags and it is absolutely essential that 1) I do not have to recreate the whole list of the tags, meaning all such words I type in should be auto-filled and 2) I can continue to cross-reference between all the notes whether they are in a single account or scattered along multiple accounts. I will be reaching 100K very soon. That's why I have this concern.
I can ask support but my rough impression, so far, is that sometimes even an expert agent is clueless about some specific points and it sometimes takes too long to hear from the team. Thank you again so much, to both of you.