Yup. As mentioned, short .com names are expensive because most of them have already been taken (that's another story altogether and it is huge). So, what's left for .com would be some not so short or not so sweet names, typically sort of long to type. The short ones are expensive, ranging from a few hundreds to even millions. The retail price for a typical .com domain in the primary market is actually less than USD10. In some places, you could get it for a few bucks for the initial year. Those that are available from the secondary market are the short ones and the expensive ones. So, your next option is .ai, which you would have a better chance of getting a short name, maybe at 4-5 letters? Yes, you are right, the .ai domain registration is manual and it takes some waiting time to register (unlike .com which you could register in minutes online), at a cost of USD100. It is also not widely available for registration by popular domain registrars such as Google Domains.
If SEO is not an issue and your B2B customers would know you by name eventually, then .ai will do fine as they will not type .com to look for your website. It seems that you have already made up your mind to use .ai. I would say, go for it. If time and funding permits in the future, try to get a .com too.
Btw, let me know the outcome of your .ai registration once you get it. I would be happy to learn about your website and also your success stories!