My only tip is to avoid using any of the more ridiculous money making short cuts as you will seriously destroy the best part of the game which is the first 100 hours starting from scratch and scrimping your way through the early ships. If you take the short cut you will be missing the most rewarding part of the game.
On the Steam Deck front, I have exclusively played on the Deck for the last 6 months when I got back into Elite. In fact it was the fact I can play it on the Deck which got me back into it. I am at the stage in Elite where all I want to to is casual stuff like material gathering, casual mining, running missions, driving around on planets in an SRV, exploring etc. Including combat, which initially was tricky to do on my Deck cos I had to really learn how to control the ships with two thumb sticks as opposed to a full on joystick, but once I learned it and set the Deck controls properly combat is as enjoyable. Full disclosure, this is with fully engineered ships, so survivability is easier, but still fun. Without engineered ships combat with Deck controls will be harder as you won't be as efficient in protecting your shield etc, but just tackle low ranked ships, or focus on getting your engineering unlocks first so you can forget about shield worries. If I was starting from scratch solely on the Deck then yes, it would be harder, but you would just take on what you can deal with at a more gentle pace, which actually would stretch out the best part of the game, i.e. the start.
Control-wise, with the two trackpads and extra rear buttons on the Deck I have all the usual functions mapped with button combos or menus on the trackpads. Really, once you set it up right it becomes second nature and it is quite remarkable how configurable the Deck is to control a game like Elite.
What I don't really do though is any Odyssey FPS stuff with the Deck. This is more to do with how fundamentally bland the FPS stuff is, but it does have to be said that framerate for the FPS stuff is only just acceptable on the Deck. But for anything in a ship, or in an SRV, the hardware of the Deck is just fine.