Could This Be SIBO Methane? Such cases?

I am a 22 year old male having digestive issues for about 5 months. My symptoms include constipation with sticky stools, a feeling of incomplete bowel movement, foul smelling gas, and bloating soon after eating when constipated. I consulted a gastroenterologist who prescribed Linaclotide and Movicol and advised dietary changes and exercise, which I followed, but I have not experienced significant relief, when I discussed with him about SIBO he refused to get me tested. About a two months ago I took ofloxacin + ornidazole for 5 days and noticed slight improvement, but the symptoms returned. I am wondering if this could be related to SIBO, especially methane related, and whether a breath test would be appropriate. Would treatment options like rifaximin with metronidazole be considered in such cases?