Catalina clean install fails

Running Macbook Pro 16 inch, so Catalina only version support (so far). Currently running v10.15.5. When I tried to do software update via system preferences to v10.15.6 it fails - it goes through the entired process of downloading etc. and when it gets to 100% of download is fails.

SO i backed up drive via time machine and decided to to a clean install and restore data. Both Recovery mode and internet recovery mode both fail in the same fashion. Downloads progress in both scenarios and ~30 minutes when it gets to end when it should being install I get error it can not be installed.

I have done disk utility in OS, and also in both recovery and internet recovery and the disk checks out fine. Not being able to update via standard OS process concerns me, which is why i wanted to do a clean install (which I can not). Even tried a bootable USB install process and that failed too.

I checked and T2 security chip is set to the lowest security settings.

I did capture the install log file in the last clean install routine that failed so I have that available to share.

Please can you provide help in getting me to be able to do clean install.

FYI - I was able to do this process on an older Macbook Pro 15 inch I have so it is definitely related to my 16 inch MBP.

Thanks.

Jim