Need help H1b extension

I came to US on 24th Feb 2017 on L1b visa. I changed my status to H1b on Oct 2018 (cab H1b through lottery). I have not traveled outside US since then.
My current H1b is valid till May 2022. As per these dates I still have 7-8 months to use up my 6 years including L1+H1b. My perm is still in process, filled on 1st Dec 2021.
My company is trying to file extension and they mentioned extension dates for 3 years (May 2022 to May 2025). Is it possible?
Am I eligible to get the extension for remaining 7-8 months or does it needs to be longer to extend?
What is my best bet please guide.

You will only get the time left from the 6 year term including any time you spent on L1B. You may claim any other time you spent outside the country during this period.
You can get 1 year extension after the 6 year maxout if your PERM is approved and you have a pending I-140 before your maxout.