This is my question too.  K-1 has created no changes to my taxes due for several years. But I will have income this year.  Do I have to have filed all those amended years showing the loss to claim the carry forward loss?

No, but you do need to keep your copies as proof, just in case! You will want to enter the carry-over losses going forward.

you may have a tax issue for not filing returns for the loss years.  under the tax laws, the NOLs from 2017 or earlier must be carried back to the second prior year. for NOLs in 2018-2020 there is a 5-year carryback unless a timely filed election was claimed to carry forward the NOL.  it may be that failure to file will result in the losses from some of the older years being  lost. you need a tax pro to go through what you did to see the availability of those losses.

note losses may be different than NOL.  you can have a loss but no NOL.  so it is unclear if you have anything that can be used in the future.