At least for teaching, have you investigated transcription devices? (speech-to-text). Maybe if you teach a class with a lot of esoteric vocabulary that might not work so well. But there is another thread on this forum that discusses the free Google Android app Live Transcribe that uses an Android phone microphone to transcribe spoken words to written text. Works very well for everyday speech. Requires an Internet connection as it uses Google servers. Maybe there is something similar for the iPhone if you’re an iPhone user.
On premium vs. less-premium HA models from a manufacturer, from what little I’ve read, the OEM’s typically say that the premium brands are designed to handle more complex, varied listening environments whereas the lesser models of the brand are designed for folks who have less demanding requirements, e.g., stay-at-home elderly people who interact with relatively few people in a quiet, consistent environment. The premium brands supposedly cost more because you are paying for the development and manufacture, etc., of higher levels of technology rather than spreading the cost around amongst all purchasers of that brand and having folks pay for features that don’t need and don’t get in their less expensive, less premium hearing aid.
I haven’t follow any of the posts about your condition very closely - especially the previous thread - but it is possible, unfortunately, to have hearing loss so severe that it can’t be adequately restored by a hearing aid. Hopefully your audiologist has been able to make some determination on that score but it should only cost several hundred dollars at most to trial a premium hearing aid and return it if you don’t think it helps. Maybe with your audiologist’s help and some friends you could reconstruct trial scenarios to compare HA performance rather than waiting to use HA’s in class and making any given class an experiment. In a trial setup situation, you could twiddle with all the settings and see if you can find the best adjustment, the best program of whatever you’re trialing to deal with your loss. Is your audiologist wanting to keep you with ReSound because they’re more experienced with that brand rather than Phonak? Maybe you should give Phonak a try or if you can wait a bit, see what focusandearnit has to say about the Marvels vs. the Quattro’s, when he gets his trial Marvels shortly. If he thinks the Marvels are definitely a step up for him from his Quattro’s, which he clearly likes, that might be the ultimate model to try - but there are also premium Widex and Oticon models out there, too, Signia, Starkey, etc.
The ReSound Smart Fit 1.3 software, which is only supposed to be used by a hearing aid provider, has some excellent media test files. Maybe your HA provider has that software installed and could give you a single group of sound files or so to play, e.g., _ENmd+0lunch.wma (the speech at 0 dB above noise), the versions with the speech at 5 and 10 dB above noise, and the speech only file. There’s also another series of speech in noise like this, the _ENkt+0bkft.wma file with similar versions with louder speech relative to the noise and a speech only version. I would think if you can’t make out the speech-only versions of these files, your hearing loss is so bad it’s not going to be reparable by HA’s - but I’m not an audiologist and am pretty ignorant.
The thing about these speech files it it would give you a highly reproducible speech in noise scenario that you can use to test out whatever HA’s you want to try. Even though um_bongo (Stephen Bright, a provider) has pointed out that the recordings, at least when played on a computer, are not true 3D sound that lets directionality of an HA work to maximum advantage, maybe it’s something reproducible that would allow you to make an objective as decision as possible about some expensive alternatives.
The Smart Fit software is also available in the DIY section and you can obtain a personal copy of the sound files I mention from that. ReSound says the software is not to be deconstructed and used for other purposes, so keep that in mind as well as the other restrictions on the program. It requires a Windows computer (works on Windows 10) and you don’t want to have the files extracted from the .ZIP download in too long a file path or the install will bomb. If you see a “can’t find markets.xml” on an install attempt, your path is too long.
Hope at least the test sound file idea is helpful in seeing how challenging a sound environment any HA you trial can help you deal with.