can’t say I have any coherent advice to give on this front. If I had the money to fill my ISA limit so early into the year I would instead have written off more of my personal debts instead.
your choices boil down to either locking the ISA in for the year, buying stocks currently at large discounts you see succeeding and holding the shares until the next tax year or being aggressive and approaching the stockmarket as a trader to try to see some fast initial growth to the account in preparation for a 2nd year spent cost averaging your positions IMO.
Try work out if you think your capital growth will hit capital gains limits before you pay tax on your dividends. Whichever you will hit first, get them in the ISA. So for example if you dont expect to hit your CGT limit but you might pay tax on your dividends, you would want distributing ETFs and the dividend payers in the ISA and put the accumulating ETFs and non dividend payers outwith the ISA.
But all depends on what you are holding and how much extra you have to invest.
I think it’s more likely to be the other way around, as I have mostly high growth stocks in the portfolio. So it’s probably better to have the lower growth but higher dividend paying stocks in the regular invest account.
Another idea I had was to try swing trading a small portion of some of the stocks within the ISA, trying to profit from the market volatility. In theory this should provide more free funds within the ISA.