Shopify Theme(1-Step Checkout/3-Step Checkout) AB Test?

[Intenso09]

I'd like to test the 1 page checkout vs the 3 page checkout. Since it can be set within the theme, my idea was to simply AB test two themes.

I used https://apps.shopify.com/theme-scientist in the past but it showed me different numbers than Google Optimize. Someone in the reviews had a similar issue, so I don't trust it to collect data properly.

Than there is https://apps.shopify.com/intelligems I'm using right now. It seems to collect only 6% or total orders it seems. It's also extremely expensive for my needs. Would be fine if it collected data properly, but it just doesn't.

There is also this one available https://apps.shopify.com/lomio-ab-testing but the reviews are not very promising.

Is there anything out there to someone is aware about? I'm shocked there is no test for this certain feature available or am I missing something?