First, please use
example.com when you obfuscate names and not other names.
Second, all the below depends on the TLD. I will assume we stay in gTLD land, which uses EPP as protocol between registrars and registries and its specific case of hosts as objects.
When you need to create a glue record, you need to do that through your registrar: it will create a "host" object in the registry database (which will trigger publication in registry authoritative nameservers, as needed). Things depend on the registry design but at least of in-domain nameservers (which trigger glues), the host object in the registry database is sponsored by the same registrar as the domain under which it resides.
As long as you do not change registrars, nothing happens regarding the resolution and the possible glue zones that the registry will publish.
In EPP, registrars can not transfer host objects between themselves BUT if domain
example.com changes registrars, THEN all host objects below it will also be automatically transferred to the new registrar. This is needed for the new registrar to be able to then manage your domain correctly, but note that this transfer by itself will not trigger any change in the DNS resolution.
Note that if you are curious, you can use the whois protocol (or now the RDAP protocol) to query the registry for data about hosts objects as well as you can do for domain names.
In your example, the first domain uses glue records, but the second one not by itself (since it uses the nameservers of the first one then of course they will have glue records, but just because they are used by first domain; if they stop being used by first domain no glue records will be needed to resolve the second domain).
So if you remove them from first domain you need to make sure that their name is still properly resolved (their names must be in first domain zonefile and hence be given in responses to queries to the new authoritative nameservers of the first domain), because if they have only the glue records, without being present in the child zone (which would have been a DNS configuration error but one that could went unnoticed), then their removal from firsts domain would make them not resolvable anymore and hence would make second domain not resolvable anymore.