Print the parts (not the assembled thing), and insert a 608 bearing in the middle before gluing on the sides. Then fill the sides with sand or something else to add a bit of weight and screw on the end caps. Tie a string to the bearing and you are good to go..

I recommend using a ceramic bearing (costs about 6$), like this one -> https://www.aliexpress.com/item/608-Full-Ceramic-Bearing-1-PC-8-22-7-mm-ZrO2-Material-608CE-All-Zirconia-Ceramic/32830043710.html?spm=2114.search0204.3.40.6f8f5f92rtYfUn&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10151_10065_10344_10068_5722815_10342_10343_10340_5722915_10341_5722615_10696_10084_10083_10618_10307_5722715_10059_100031_10103_10624_10623_10622_5722515_10621_10620,searchweb201603_11,ppcSwitch_3_ppcChannel&algo_expid=791e3a06-5619-4a98-89a2-a1fd50d19b11-5&algo_pvid=791e3a06-5619-4a98-89a2-a1fd50d19b11&transAbTest=ae803_1&priceBeautifyAB=0