I’ve never studied the mechanics of the vhf but I do have Thousands of miles of offshore hands on experience. I have a lot of buddy’s that are offshore guides. I took their recommendations years ago to get the best range for my radio. They say to get a radio with a quality final amp for transmitting (usually the expensive one lol) and use a quality 6db antenna for reception and transmission. Then raise it up as high as possible. They say the antenna needs to be in great shape to keep the range at its best. They also said that if you are using a weak antenna, it could damage the final amp in the radio when you transmit.
I know that transmitting without an antenna attached used to be a death sentence for radios. I don't know if today's radios are better protected but I wouldn't try it on purpose. As you mentioned, a bad connection, especially at the antenna radio connection can look electrically like no antenna. It all related to impedance and the SWR ( standing wave ratio) factor. That's about all I remember from college.