The UK is largely unchanged from before Brexit. Its economic performance is similar to the rest of Europe. It continues to trade with and cooperate with other European countries, whilst also building stronger links with the rest of the world too (see Aukus for an example).

The predictions of all the bad things that'd happen on leaving were all incorrect. There was no 800k job losses, closed airspaces, trade wars etc.

I'm guessing you live in GB. In NI tensions are higher due to it (unionist opposition to the protocol), shipping's often more expensive, or items won't be shipped to us (try putting a BT postcode into displate, or ordering batteries online), and it's more difficult for companies to operate on an all Ireland basis. We also have "only for Northern Ireland" items in shops which are items that can't legally be sold in Ireland or GB despite being identical, in a shop like Tesco that operates in all 3 areas, causing more difficulty to shops than necessary. Here we've only seen negatives, in an area with a complicated relationship with borders, where the single most effective thing we had to deal with that was a set of common laws and trade area (europe), and none of this was even considered by Westminster before the referendum.

Edit: forgot to mention this. Someone in my family has a vehicle in Ireland and in NI, we sort of live between the two countries, pre-brexit that was completely fine as their drivers licence was european so there was no issues, but post-brexit they cannot get insured in Ireland due to insurance companies refusing to give insurance to someone with a non-EU licence.