Hi,
Because I doubted my reseller hosting, I bought a hosting package elsewhere with very good performance. I installed Joomla 4 on it. I have checked GTMetrix what the score was.
A-score:

Then I installed SP Page Builder Pro in combination with Helix Ultimate. After that I created 1 homepage in page builder and chose a standard layout (Ad Agency). Then scanned again with GTMetrix, and see how poorly the website is performing now.
C-score:

After this I turned on conservative caching, turned on GZIP, set SP Page Builder to Production mode, and on the Helix template I disabled Compile SCSS to CSS. After that it was even worse!
D score:

I always thought that the problem of slow websites was with my reseller hosting server, but it seems that Helix and SP Pagebuilder are not as lightweight as they are made out to be.
What is your statement?
Regards,
Remco