Yes, zipways is bestways.
Short: No, different blender version wont affect other version - only default .blend file association.
On windows since 2.81 Blender default installation path is %Program Files%\Blender Foundation\Blender «version»\
and instaling new version wont be delete/overrite older version
also usersettings of different versions are stored in separate folders
in %appdata%\Blender Foundation\Blender
Due to all that installing new version wont affect older version, and you can always use older version if You have some troubles with old blend files. But different builds from same version (buildbot/ecycles/release/custom) will share settings.
Each installation is rather small 300-370MB so if you are not running low on space don’t bother on deleting it right away.
We are aware of the buildbot builds anyway and they are usually pretty stable, so when we see a release as just a number for the studios and the less savvy folk…
size is steadily growing
Win is around 350 MB now
each new version is adding MB
soon will be a 1 GB
The main reason for the size increase is Blender making use of more and more external libraries (such as Mantaflow). This leads to a larger and more powerful feature-set, but at the cost of app. size.
The only way otherwise is to develop everything from scratch, but that is impractical unless you have a massive team of PhD level coders.
I don’t see why making their own solution would take up less size ?
That depends largely on how much of a library is actually used. As an example, you can import say, numpy in a python project and only use it in one place for one thing. Now you have the entire library for one handy thing. As an alternative, you could extract from numpy the relevant parts you need and put that in separate files, but then you have to maintain that part, too instead of just being able to update numpy.
I’m not sure how much that applies to blender, but that’s the general idea behind shrinking install size and libraries.