RikkiWizard
The link to information about local sim card options contains rather out of date info. For example Telia's Super card has a great Super X tariff and you are not limited to topping up by SEPA as you can top up with a bankcard within their Super app, which available thru Google Play Store
As for ATM. Apart from SEB and Swedbank, you should also be able to use Luminor bank.