How do I update the theme from the wordpress dashboard?

when i inspect your (suspected) homepage your on Enfold: 4.2.3 and WP: 5.6.3 – but even with version 4.2.3 the update step is so big that I would also recommend updating Enfold via ftp first, and then updating to WP 5.7.1.
It is also recommended to check the php version with your provider. For me Enfold 4.8.2 and WP 5.7.1 runs stable on php8.

And your WordPress Version is ?
( maybe read here : https://wptavern.com/after-11-years-users-will-be-able-to-update-themes-and-plugins-via-a-zip-file )
Since WP 5.7 you can Update via Dashboard on : Appearance – Themes : “Add New” – “Upload Theme” – then insert the new Enfold.zip file ( be sure it is the installable zip file only ) – and click “Install Now”
This Wordprss will recognize that it is an always installed Enfold and will ask what to do with the older one.
You can click : “Replace”.

On former times there was that liitle Plugin “Update Theme and Plugins from Zip File” that offers this feature – but now WordPress has implemented that.

But: – for me the safest method is and remains the way via ftp upload.

no private massage for me – so i’m out of support here.

one important point is the included jQuery Version – which is now 3.5.1
The New Enfold 4.8.2 will run under these conditions. But if you are running a child-theme with a few functions.php snippets inside – it will be important to look if you have some functions in it with:

$(window).load(function(){
// which is now deprecated and should be replaced by:
$(window).on('load', function(){

// and same thing here - the 
.click(function(){
// now replaced by:
.on('click', function(){

i would try on a page where you have a good backup the way i’m talking above with dashboard and uploading the installable zip file of enfold.
This is probably the most time saving way.
The other way via ftp upload is the safest way, because you still have that rollback then.