I also have this problem. Here are some tips I've found useful.

-- When possible, do things that you're passionate about. Develop your passions and try to work within those constraints.

-- Have a single monitor

-- Create a TODO list. Also start the day or working session with planning.

-- When tackling new problems, try to do the easiest tasks first to build momentum, before tackling harder tasks

-- Break down tasks into the smallest components and do them one at a time

-- Give yourself a reward for doing a small section of tasks (ie. watch a YT video)

-- Develop your self confidence and create a strong passion for competition, that's driven me past a lot of my attention problems