Users don’t see them
According to Baymard, 27% of users overlook the hidden content in the inactive tabs.
The example below from Crutchfield contains horizontal tabs.
An accordion (expandable tabs) or a long expanded page with sticky tabbed navigation on scroll both perform better than horizontal tabs.
Here’s what an Accordion looks like:
Sticky TOC bar
And Adidas has implemented the second option, the sticky “table of contents” nav bar:
Both options work
So my recommendation is to go for one of those two variants mentioned above, either an accordion or a sticky navigation which auto-selects the current section as you scroll down.