Slow Dashboard Performance

Hello Forums,

I’m new to this group and hope you can help.

I have a WordPress Platform, which was developed years – as opposed to months – ago. However, it has been in cotton wool with very little content added for a long while.

I’ve decided to revive the site but find that the backend/Dashboard is performing at a very slow rate – it takes around 20 seconds to switch from one of the functions in the Dashboard list to another.

The speed from the front end of the website for visitors is acceptable.

The site is hosted with IONOS and has been for the last three years – although it was hosted with Names for almost five years previously and functioned well then.

IONOS has informed me they can’t help with this performance issue and that I have to consult WordPress.org.

The WordPress developer of the site is no longer available.

The site is asking to be updated to WordPress 5.5.2 and there are 16 plugins which also need to be updated.

Do you think simply by updating to 5.5.2 and the outstanding plugins will resolve the speed issue, or does something else have to be addressed?

I do also require a WordPress developer to make some tweaks to the site.

Look forward to hearing from an expert with some good advice; thank you.