Missing Block Groups

I'm comparing block groups in two publications: TIGER/Line shape files and their ACS 2019 estimates.  I'm finding as much as a third difference in the block group keys between the two. Looking just at Florida (FIPS 12) as an example:

• ACS                 https://www2.census.gov/geo/tiger/TIGER_DP/2019ACS/ACS_2019_5YR_BG.gdb.zip
• TIGER/Line      https://www2.census.gov/geo/tiger/TIGER2021/BG/tl_2021_12_bg.zip

Their block group IDs differ this way:

• TIGER/Line file has 13,388 block groups in the state.   ACS has 11,442 block groups.
• TIGER shapefiles have 5,255 block groups NOT available in the ACS set.  For example:

'121030255091', '120210003014', '120190312022', '120090651272', '120110703291', '120990019073'

• ACS has 3,309 block groups NOT available in the TIGER shapefiles

'120570116071', '120690313112', '120860096001', '121113820034', '120860058025', '121050124032'

I understand some block groups may be suppressed in the estimates, and of course there are incremental changes in block group definitions over time. But, these do not explain the size of the difference here.  Can you help me reconcile these?

Thanks in advance!

Michael