Hi badguyus1776. Welcome to the forums, and I'm sorry you are concerned that you have signs of ADHD. I don't know if there is a tendency for people with a history of TS to develop ADHD, per se. A lack of focus and interest in certain activities, like the painting you mention, could occur for a number of reasons.
As we age, nutritional needs can increase or change. You might want to consult a practitioner who could order some lab work, if that's an option. You might have an imbalance with amino acids or other nutrients that often affect attention. Would you be interested in doing that?
A mild depressive state could result in the symptoms you describe. Depression might be addressed through the biomedical approach just mentioned. Does that make sense? Do you already take brain-related supplements?
Something else that can change with age is food reactions. Think about whether you feel the same every day or if there are times you feel more energized and engaged. You could keep a log of the foods you eat and consider whether you feel different on various days based on what your diet is like. Cutting back on sugars is often recommended for ADHD. (I don't know what your diet is like presently.) In addition to that, food intolerance can develop that causes brain fog. As an example, some people can no longer handle alcohol the same way they used to--or they start to react to gluten or certain foods with headache or foggy head or stomach issues even though those items never bothered them before.
Since you mentioned indoor painting, I'll pass on a suggestion--and that is to go with non-VOC paint once you get inspired. It is available from major paint companies and is much healthier than standard paint. Some people find tics increase significantly with exposure to the chemicals off-gassing in standard (smelly) paint.
Link to Sherwin Williams eco-friendly paint with explanation
I hope that helps? The good news is that ADHD-type symptoms can often be improved.