I had the same issue last year and it took me ages to solve it. I updated my Poco F3 xiaomi.eu MIUI 14 ROM which this time requires flashing Magisk again. Their guide worked, just not for Halifax.
https://xiaomi.eu/community/threads/how-to-flash-magisk-and-play-integrity-fix-on-xiaomi-eu.70553/
I don't know the exact setup required and I don't want to mess with it now either, but what is currently working for me:
Magisk Delta 26.1 (26100), Play Intergrity Fix v13.3, Skamiko, v0.74 (188). (They're all the latest versions as of this post, but I listed them anyway.)
'Zygisk' enabled, 'MagiskHide' enabled, and in 'Configure MagiskHide' I have Halifax, Google Play services, Google Play Services for AR and Google Play Store checked (with all the toggles inside each on.)
My fingerprint Halifax login doesn't work, but it didn't previously either.
Like I said, my setup was different the last time I did it almost exactly a year ago. There's no way I can remember it. I do recall some specific toggles in 'Google Play Store' deny list, etc. From my downloads, I can see I was using Magisk Delta, Saftynet Fix, Magisk Hide Pros Conf, and Shamiko.