No. You can have multiple OWA mailbox policies within the tenant, however only a single one can be applied to a given user.
Multiple Outlook Web Access Mailbox Polices Behaviour

Can multiple OWA mailbox policies be applied and if so how are they handled/merged?
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Vasil Michev 119.5K Reputation points MVP Volunteer Moderator
2022-03-04T17:59:57.707+00:00
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Joyce Shen - MSFT 16,701 Reputation points
2022-03-07T05:45:20.85+00:00 Hi @shockoMS
Agree with michev, we could create multiple OWA policies in your organization, and you could also assign different user with different OWA policy
However, Only one Outlook Web App mailbox policy can be applied to a mailbox.
You could refer to the steps introduced here: Outlook Web App Policies in Exchange Server 2016
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