I have a Quantum LTO-7 drive (6-TB tapes) bought many years ago for $3000.

Today I would strongly recommend against buying a LTO-7 drive, as it is obsolete and you risk to have a tape collection that will become unreadable in the future for the lack of compatible drives. A LTO drive can read 2 previous generations of tapes, e.g. a LTO-9 drive can read LTO-7 and LTO-8 tapes. LTO-10 drives, when they will appear in a few years, will no longer be able to read LTO-7 tapes.

The current standard is LTO-9 (18-TB tapes). If you write today LTO-9 tapes, they will remain readable by LTO-11 drives, whenever those will appear.

Unfortunately, LTO-9 is a rather new standard and the tape drives, at least for now, are even more expensive.

For instance, looking right now on Newegg, I see a HPE LTO-9 tape drive for $4750.

Perhaps it could be found somewhat cheaper elsewhere, but I doubt that it is possible to find a LTO-9 tape drive anywhere for less than $4500.

If you need to store at least 200 TB of data, you may recover the cost of the tape drive from the difference in price between LTO-9 cartridges and HDDs.

Otherwise, you may choose to use a tape drive for improved peace of mind, because the chances for your data that is in cold storage on tapes to become corrupt are far less than if it were stored on HDDs.

I have stored data for many years on HDDs, but the only thing that has kept me from losing that data was that I have always duplicated the HDDs (and I had content hashes for all files, for corruption detection, as the HDD controller not always reported errors for the corrupted blocks). After many years, almost all HDDs had some corrupted blocks, but the corrupted blocks were not in the same positions on the duplicated HDDs, allowing the recovery of the data.