We know coffee affects absorption of levothyroxine doi.org/10.1089/thy.2007.0222 but there have been no studies showing a similar effect of tea. This new study doi.org/10.3389/fendo.2022.... shows that tea had a similar effect to coffee.
They identified 37 out of 2,000 patients for the trial. This suggests only 2% of patients need worry about tea or coffee affecting their levothyroxine medication. The authors feel the problem lies with tea and coffee affecting the dissolution of the tablets.
I usually take my levothyroxine and liothyronine with orange juice and no tea / coffee. When on holiday I often have a coffee a few minutes or so after taking my tablets and have not noticed a problem. It may be that I don't notice a fall in levothyroxine absorption because I take liothyronine. It could be that the acidity in the orange juice is sufficient to overcome the effects of coffee - I'm waiting for a combined orange juice / coffee study! (We all know combination therapy is better, including breakfast drinks).
I would urge people not to worry about this unless they have absorption problems.