Applying for a PhD in Theoretical Physics without Undergraduate Dissertation?

I’m considering applying for PhD programs in theoretical physics but didn’t complete an undergraduate dissertation due to my degree structure. My degree (UK) initially followed an integrated master’s (MPhys) route, which didn’t offer a dissertation option. I later transitioned to a BSc instead, as I plan to pursue a taught master’s course in theoretical physics (e.g., Part III Maths at Cambridge).
However, I have done research experience through internships in theoretical physics in my undergraduate studies. Would PhD admissions committees view the lack of a dissertation as a disadvantage, or would research internships compensate for it?
Has anyone applied in a similar situation, or does anyone have insights into how admissions panels assess this?
Thank you!