After 20 years working from home... I honestly feel I have my 'perfect' home office environment. Some things that have really made a difference:

  USE SEPARATE COMPUTERS FOR WORK AND PERSONAL STUFF
  If you can swing the space/money etc - this is the
  single biggest (best) change you can make. It SO
  much easier to focus when all your favorite stuff
  isn't staring at you on the desktop!

  Create separate profiles with separate shortcuts
  for personal and work browsers (per-client if
  needed).  Much easier to resist 'tab roulette'
  if you have to open a separate program to do it.

  Don't keep a radio or TV in your work space.  If
  you like music while you work - use local 
  playlists or streaming services that won't 
  inject 'news' or ads into your music.  Its really
  easy to hear some news tidbit and spend 20 minutes
  reading up on it. Or you might hear an ad that
  sends you off to see if it's really a good deal.

  I prefer audio calls over all other formats. If 
  you 'chat' you usually only get half of the other
  persons attention, and its just much lower 
  'bandwidth' then spoken word.  The current video
  craze just ends up with people 'playing' with the
  new 'toy' - wasting time talking about their new
  background, filter, or the home reno project in 
  the background.

  I don't share the worlds fascination with cell
  phones - I basically never check mine.  It 
  probably has 5 years of unread voice mail on it.
  (I just use it for 2FA and lyft).  However, if 
  you require a phone for checking websites, etc. 
  Get a dummy phone, and leave your personal phone
  in another area. (Do NOT install social media on
  the dummy phone!)

  Make sure your chair supports you properly.  If
  needed you can improvise back/butt support with
  those airline neck pillows (place them backwards
  with the opening in the back to prevent sitting
  on your tail bone). You can also use inflatable
  'donuts' or towels if need be.  If possible, 
  get a 'real' office chair with full ergonomics
  (can be really cheap at used office supply stores)

  I find a good over-the-ear wireless headset great
  for both blocking out random noise (leaf blowers,
  lawn mowers, whatever) and use in voip calls.

  I'm blind as a bat, so I have 3x4k monitors with
  huge font sizes and dark themes with high contrast
  This allows me to work with a lot less eye strain
  while still keeping 3 full size windows visible.

  Ugghh..this is getting really long...
  time for a smoke!