https://buildyourstax.com/ is an investment game - you can play it while you wait for your ISA to warm up.
Good: has some ok info explaining savings, CDs, gov bonds, index funds, commodities, individual stocks. It uses the historic data of a 20-year period (but doesn’t tell you which until the end). It is quite fun.
Not so good: there are obviously limitations because it simplifies things. The 20 year clock is quite compressed so you’re clicking manically. I have not beaten the computer.