Smart controller for Renewaire Premium X

I gave up on the Zehnder ERV mostly because of price, and I am running round metal duct. Instead, I purchased a Renewaire Premium X. For the initial install, all I need is push-button timers. HOWEVER, the controller needs to support seven push buttons (6 bathrooms and the kitchen).
Renewaire support, all the way up to engineering, says they can only support six buttons and that I should get a third-party controller.
The BACnet controller supports it, but it is very expensive, and I don’t need or want that level of complexity.
Just seven timer buttons (would prefer not to use slider switches) and the option to add in the future CO2 and maybe some other sensors. Please help.
New construction at 8500ft in Fremont County Colorado. Zone 5a. I am going to add some silencers and large standard-sized filter boxes. There is a plan for pre-heating fresh air on days when the outside temp drops below a set temp.
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The PBT is one button, you can connect 6 PBLs to it, so 7 buttons in total.
I think a simple paddle switch between 24 and boost will also kick the unit into boost mode, so you could wire that for that for say the kitchen since you will want to run it longer. You could also put a mechanical twist timer on one of the least use bathrooms.
EDIT. For an external paddle switch or twist timer, you'll need a 150 ohm resistor in series.
Thank you so much Akos, I will call Renewaire technical support tomorrow to verify and get the exact wiring connections. They were so certain there was no way to do it. Do you work for Renewaire?
No but my day job is dealing with complicated electrical systems, lot of my world is reading datasheets.
The pdf for the PBT shows exactly what the setup I was referring to.
https://renewaire.com/wp-content/uploads/2017/09/PTL_InstructionSheet_140465_008_APR20.pdf
Good luck with your install.