Categorising a large amount of products across categories and sub categories. Getting mixed results

Hi. We are trying to categorise 1000s of components across categories and sub categories. We are getting mixed results with prompting. One shot prompting sometimes messes things up as well. We would like to get at least 95% accurate results. Around 80% is achievable only through the best models currently out there. However, this is going to get expensive in the long run. Is there any model that does exactly this specifically? Would we have to fine tune a model to achieve it? If yes, then what models are good for categorisation tasks which could then be fine tuned. 30b, 7b etc off the shelf were useless here. Thank you