Almost every site I am asked to speed up has already been told it needs a rebuild. Most of them do not. What they need is images at the right size, caching configured properly, a plugin audit, a database clean and hosting that is not the bottleneck.
That work takes about a day and it costs a fraction of a rebuild. I do it first and tell you the result honestly, because finding out the platform was never the problem is a good outcome for you even though it is a smaller invoice for me.
A performance report on your home page on desktop tells you very little. Your actual visitor is on a mid-range Android phone on a mediocre connection, landing on a long service page or a checkout, often at a busy time of day.
So that is what gets measured: real pages, mobile, throttled, before and after. Field data from Search Console rather than lab scores alone, because the score you can screenshot and the experience your customers have are not the same number.
Core Web Vitals gets discussed as a score. It is really three separate questions about the experience, and knowing which one you are failing tells you what to fix.
The reason to separate them is that the fixes barely overlap. Compressing images does nothing for a page that is slow to respond, and trimming JavaScript does nothing for a hero image that is four times larger than the slot it renders in.
WordPress runs roughly 42% of the web, which makes it a large target. The honest position is that it needs maintenance rather than luck: current core, themes and plugins, a security layer, real backups held somewhere other than the same server, and someone paying attention.
I work with MalCare and BlogVault for hardening, monitoring and backup, and I handle malware cleanup and recovery when a site has already been compromised. If you have been hacked once and nothing changed afterwards, you will be hacked again.
I will not chase one, and you should be wary of anyone who promises it. A perfect lab score on a page nobody buys from is worth less than a good real-world experience on your checkout. I optimise the journey your customers actually take.
Often no. Both major builders are fast enough for most sites once the images, caching, plugins and hosting are sorted. If after all that the builder is genuinely the remaining constraint, you will know, and it will be an evidence based decision rather than a suspicion.
The audit and cheap fixes are usually a day or two. Deeper work depends on what is found. You get the measurement first, so you can decide how far to go.
Start free: test your longest page on mobile with a throttled connection, and count your active plugins. Send me both numbers and I will tell you roughly what you are dealing with.