It says the same thing I just said. Did you read the report or just the summary? The summary looks like some civil service bias, as it doesn't actually state the most important facts to know clearly. But the report itself does make it clear.
Look at the actual PDF, in particular the graph on page 12 (JIM7/JIM8). This is inflation adjusted goods trade. As you can see Brexit has had no impact whatsoever. Inflation adjusted goods imports are about where they were in 2018. Inflation adjusted exports are about where they were in Jan 2020.
There was a very brief drop in both when the new controls came in. The disruption lasted only a period of months before trade resumed as before.
In other words, there's nothing to see here. This is the opposite of what was stated as 100% certainty by supposed economic experts. Anyone who said before the vote that leaving wouldn't have bad economic consequences was roundly shat upon as a expertise-denying dolt. Yet they were correct.
In terms of % of the total trade, it's the lowest ever in 2022.
The report states clearly: "The proportion of the UK’s total exports going to the EU has generally been declining gradually over the last 15-20 years". It's due to the rise of China/India as more important trading partners, so that would be expected even if the UK had stayed in.
Now look at the graph on page 15. It shows a smooth long term decline in the EU's importance as a trading partner. In particular there was no drop in relative exports to the EU after Brexit, again, despite clear promises that it'd have a huge effect.
What we can see from the report you cited is two things:
1. What I said is correct. Brexit has had no impact on trade. This shows up clearly when using inflation adjusted statistics - it's all a continuation of prior long term trends. Therefore by implication, EU membership was useless for the economy and the entire basis of the Remain campaign was therefore a lie (but did they realize that?!)
2. It's very easy to be misled by Remain bias in the establishment. The summary for "statistics on EU-UK trade" doesn't mention the lack of Brexit impact anywhere despite it being the most important result by far, with the result that you thought you were contradicting me without doing so.