They don't make things like they used to! I can remember when Windows PCs were known as IBM Compatible PCs because IBM (International Business Machines) established the industry standard for PCs and there is reason for this, there machines were solid and stable and properly engineered so changing something like a CMOS battery in an IBM ThinkPad R32 is not only documented in their Hardware Maintenance Manual (AKA service manual) it's very easy to replace!
The hardware maintenance manual for the IBM ThinkPad R32 is available on the Internet Archive here: https://archive.org/details/ibm-service-manual-thinkpad-r32.pdf
The CMOS battery is hidden under the keyboard so all you need to do is turn the laptop over and remove these two screws:
You then need to slide the keyboard back a bit..
Carefully lift up the keyboard, there is no need to disconnect the keyboard (but you can if you like)
Apparently there is a risk of explosion if you incorrectly install the 3V battery - not sure on this one! 🤣
Where Can You Get A Replacement Battery From?
They are still available on places like Amazon and eBay as all they are, are a CR2032 3V battery on a 3 prong cable with a JST connector on the end.
Or, you can do what I do and re-use the existing JST connector/lead and make your own:
If you want to have a go at making your own CMOS battery then here is a link to a YouTube video I made some time ago: https://youtu.be/d7gmbnMD7PU?t=71