Any tips for playing lux?

Ward

200k mastery lux player here. And ima tell u there's not really much you can do once you encounter j4 face to face. Based on your op.gg, i can see that the j4 built , providing him with enough movement speed to possibly even make ineffective for you. Read other comments on how to use Q.

E is an underestimated ability that i rarely see people use it properly. Aside from just damage, you can use it for checking bushes by throwing E into a bush to avoid melee range encounter with j4. And if you see enemy in the bush, dont detonate it immediately; another use for E is the AoE slow, which is probably what u need the most against a user. Let the 45% slow on E do the job for u instead of using it for damage, and run. If you see j4 approaching you from far, u can first-cast E on his path to create a 45% slow zone so that he cant chase you down. Yes, he can definitely dash thru it but then to negate the slow completely, he'd have to dash from edge of your E to land on the other edge of the your E, which might work on ur favor since he cant just dash as soon as he sees u. If the j4 is skilled tho, u probably have no hope; there's a reason is frequently played in LC$ while is never played in LCS.

Save your Q for peel. Especially if there's a j4 or an assasin on the other team. Most are pretty telegraphed in their approach. Hit them with your Q while they walk up to you, so that you don't get jumped.

Also, positioning. If j4 could ult you without going through your teammates first, then you're either in the wrong place on the map or standing too far forward.

Spam your laughing when you can.