Installing a hard copy serial number on a new laptop?

Thank you to everyone who replied. Now I know where I'm at! 

LR6 should run as a 64-bit application under Monterey but installing it is the issue; you must boot into an OS that can support the 32-bit installer (the last being Mojave). That's a big problem for M1's because Monterey, Big Sur, Catalina and M1 Macs do not run 32-bit and can't boot into Mojave. 
IF your new MacBook isn't an M1, you are OK but if it is, you're SOL. 

If you can't deactivate a serial number you have to contact the Adobe support. Only they can reset the activation counter.
 

This is a public forum and not the link to Adobe support. We're all normal users as you are.
Sorry, nobody here can help with an account or payment problems
 

Be sure to be signed in with your Adobe ID before accessing the link below.
Do be aware that Adobe's staffing is also impacted by the virus and so wait times can be a little are longer. Make sure that your browser does NOT block ads, scripts, or pop-ups.
Please allow 'cookies' in your web browser for the link to work
 

This link will go directly to the chat option
Type "Agent" in the chat box to bypass the chatbot and be connected to a person
-Meaning type in the word Agent without the quote " " marks
https://helpx.adobe.com/contact.html?rghtup=autoOpen
 

ASK ONLY FOR ACTIVATION SUPPORT TO ADJUST YOUR ACTIVATION COUNT
You may have to be PERSIST or TRY SEVERAL TIMES to find a more experienced support professional.

-------------------------

One Adobe Support person willing to reset Lr6 Activations is @Careeeesa

Send her a Private message by clicking on her profile.

You will need to state your Adobe Account ID and provide a valid Serial Registration Number.

Please note:

You can't install LR 6 on Macs since 10.15, since even though LR 6 itself is 64-bit, but its installer is a 32-bit program and Apple discontinued support for 32-bit programs. 

If you have a new MacBook, then no doubt it will be running a version of MacOS that does not support 32 bits applications anymore. The installer on your CD is 32 bits, so it is not going to work. Forget about Lightroom 6. It is ancient, end of life. If you really do not want a subscription, then Lightroom is not for you. Get some other application to manage your photos, like the free Apple Photos that came with your Mac.