If it doesn't run in a browser, "cloud" host and mine customer's data, and have an ARR subscription, it might be time to dust off old-school models... :)
I used to develop expensive technical workstation software (in Engineering, but I was always friends with Marketing, and picked up some bits).
My naive engineer's idea of one model is that you offer all of:
1. Start by selling a particular version by the "seat" (say, number of simultaneous users) or "site" (maybe up to N users at a particular company, especially with WFH). (Probably you provide free minimal updates for any security and other critical defects to this exact version, but hopefully you have zero of those.)
2. Recurring revenue from support contracts. This entitles the customer to the latest version at any time, as well as responding to their questions. (Your latest version is for landing new customers, as well as additional reason to keep customers on a support contract.) Maybe you make 1 year of support contract a mandatory (maybe discounted/free) part of the initial sale, to help customer be successful, and then they can decide whether to renew, or keep running the last version under their contract period without further updates or technical support. I think this keeps you from having to maintain many version maintenance forks (except for security and other critical defects, so there's your incentive to not make those defects :). You do want to have smooth backward-compatibility, to reduce customers getting stuck happily on old version, resistant to updates (effort, fear, dealing with IT), and then see less reason to keep paying for support contract.
3. One-time or recurring revenue from training. This at least used to be significant, even when the one-time software cost alone is 4-5 figures per seat. Each training purchase involves scheduling training days/weeks with highly-skilled trainers on-site, and expensive employees all scheduled to receiving the training at the same time. Maybe you also have free async training videos and tutorials, and only really deep-pocketed customers want to spring for the on-site/virtual live trainer.
4. Systems integration and customization consulting. Some of this might be tightly paired with sales/marketing, such as systems engineers that are paired with sales, and solve gap problems as part of closing the sale. But customers might have bigger tasks they want to pay you to do with your software and their software/business.
Oh yeah, and maybe additional modules or complementary product, that maybe are huge specialized functionality that one wouldn't expect to be part of the core product (for which they're already paying a support contract to get whatever new features you add to core).
I used to develop expensive technical workstation software (in Engineering, but I was always friends with Marketing, and picked up some bits).
My naive engineer's idea of one model is that you offer all of:
1. Start by selling a particular version by the "seat" (say, number of simultaneous users) or "site" (maybe up to N users at a particular company, especially with WFH). (Probably you provide free minimal updates for any security and other critical defects to this exact version, but hopefully you have zero of those.)
2. Recurring revenue from support contracts. This entitles the customer to the latest version at any time, as well as responding to their questions. (Your latest version is for landing new customers, as well as additional reason to keep customers on a support contract.) Maybe you make 1 year of support contract a mandatory (maybe discounted/free) part of the initial sale, to help customer be successful, and then they can decide whether to renew, or keep running the last version under their contract period without further updates or technical support. I think this keeps you from having to maintain many version maintenance forks (except for security and other critical defects, so there's your incentive to not make those defects :). You do want to have smooth backward-compatibility, to reduce customers getting stuck happily on old version, resistant to updates (effort, fear, dealing with IT), and then see less reason to keep paying for support contract.
3. One-time or recurring revenue from training. This at least used to be significant, even when the one-time software cost alone is 4-5 figures per seat. Each training purchase involves scheduling training days/weeks with highly-skilled trainers on-site, and expensive employees all scheduled to receiving the training at the same time. Maybe you also have free async training videos and tutorials, and only really deep-pocketed customers want to spring for the on-site/virtual live trainer.
4. Systems integration and customization consulting. Some of this might be tightly paired with sales/marketing, such as systems engineers that are paired with sales, and solve gap problems as part of closing the sale. But customers might have bigger tasks they want to pay you to do with your software and their software/business.
I'm sure others can improve upon the ideas above.