Replacing my laptop later this year will cost ~$2k, along with endless time and attention and so much otherwise-useless knowledge to keep it operating and secure and configured. I get bugged every day by software asking me to watch an update download. Every time I boot my computer 2 or 3 different game clients somehow all have 50 - 100 meg of updates.
None of that helps me write web apps.
You should start by setting up a proper environment on your PC that is "distraction free". You are not going to be more productive on a phone when it comes to writing web apps. All is required on a PC is a cli with SSH and a browser. I'm saying that as I'm typing on a $250 dollar laptop that I use everyday for Java development, and it still boots under 10 seconds on windows 10.