Hi, if starting from a Closed position it is doing what it is suppose to be doing, loading your homepage.

You can use another Homepage or add another tab by putting a Vertical Line ( | ) then the address of another site or about:blank so 2 tabs load at once and you can go back to the other page later.

If you do not use it turn it off or : https://addons.mozilla.org/en-US/firefox/addon/new-tab-override/

With a older computer and little ram with drivers that possibly have not been updated like your Network Card, things will be slower.

Quantum does lag upon startup as it "looks" to various domains to retrieve various types of data such as "Recommended by Pocket" , "Snippets", and Highlights". Loading of the default homepage should be faster if those 3 data type features are disabled in about:preferences#home . A slow connection or slow server can cause additional delays in Firefox being ready to use as it waits for the data to arrive in Firefox.

The first launch of each day is the slowest due to Firefox looking to the updates servers for a Firefox update and updates for Add-ons; launches later in the day Firefox doesn't look for for updates, but the homepage data will still load fresh data. And if you are using Sync, Firefox will look to the Sync server for changed data with every launch throughout the day.

Having a blank page for my homepage is a real help for startup speeds and for Firefox to be ready to use almost immediately.