SH dual eligibility and TH question

Plan has dual eligibility for deferrals and SH Match.

I understand that removes the Top Heavy 'pass' plans often get.

The Plan has like 10 participants, everyone has been there several years. Plan is 80% TH.

Are they subject to the TH minimum every year?  Or is it just for years where there is someone new and they are not eligible for the SH Match?

(We have since amended the Plan to have the same eligibility for SH as deferrals.)

Look at it as...

Yes, they're subject to the THM every year.

Now, do they have an exception they can apply?

Wouldn't someone brand new be an otherwise excludable employee and therefore possibly excludable for THM purposes as well on those grounds?

Deferrals are 3 month wait, but SHM is one year.

But are they still subject to the TH even though everyone in the plan has been eligible for SHM since 2020? (No new EEs in the interim.)