Why form frequently freezing especially on mobile?

Many people complain the form is freezing on them, especially via mobile ph. Can you advise any helpful tweakings please? I just turned on 'continue forms later' as suggested in another help thread.

It's also a rather long form, and I'm wondering if it would be less lightly to freeze if it wasn't all on one page?

Thanking you xx

I tested the form and it's working fine on my end. The form is not lagging and it is mobile responsive. However, I noticed that the form isn't centered on mobile devices.

Please inject this custom CSS code to your form:

.form-all{margin-auto!important}

Guide: How to Inject Custom CSS Codes

Give it a try and let us know how it goes.