[Samba] Questions about samba upgrade

[Trenta sis]

Hi,

I'm making tests to migrate our actual 4.4.5 to a latest versions and
add a second dc.

I have added a second dc with 4.10.7 and seems to work fine, now I
have 4.4.5 with fsmo roles and a second dn with 4.10.7, but reading
wiki https://wiki.samba.org/index.php/Upgrading_a_Samba_AD_DC seems
that since latest days some changes about steps to upgrade, now seems
that is recommended to us in-place for 4.4.5

----
Update one Samba AD DC that does not hold any flexible single master
operations (FSMO) role, or else the DC with the least roles.

For upgrading to a new release, most users should simply follow the
'in-place upgrade' steps above.
Advanced users upgrading to a new major release may want to consider
using the 'DC rejoin' steps below.


Joining a DC to domain can be a troublesome process for some users,
and it can be difficult to recover your DC if something goes wrong.
Only consider using this approach if you are an advanced Samba user,
and are running a modern Samba installation (i.e. v4.7 release or
later, with a minimum 2008R2 base schema). Only use this approach for
major Samba version upgrades (e.g. v4.10 to v4.11).
---

But also appears that is best to use join:
Rejoining the upgraded DC has some benefits for your AD database over
in-place upgrades.  --> What are these benefit?

Anybody can give detail about advantages and disadvantages about two methods?
what is the recommended in my case, 4.4.5, 1 dc and I need to migrate
to 2 dc, both with 4.10.7


Also I like to have an alternatives option/backup in caise of failure,
can I do a snapshot of 4.4.5 samba server with samba stopped, before
migrate and join new servers,... and in caise of any error revert to
this snapshot? All machines and users will work If I have to revert to
this previious state? I understand that new users/machines added after
machine will be lost

Thanks!