I was the Administrative Officer for the Psychiatry Service at the Sepulveda VA Medical Center, which was part of UCLA's San Fernando Valley Training Program. All of the Medical Staff were UCLA Professors and Principal Investigators on funded research at the highest levels. It housed one of six Geriatric Research, Education and Clinical Centers in America. These centers advanced or knowledge of the processes involved in loss of mental acuity in older populations. i don't know one one-thousandth of what the least knowledgeable of their staff knows. But, I do know that none of them, none of the psychiatrists, psychologists, clinical social workers and nurses I worked with would agree with your assessment.
No health care practitioner worth their salt would make an assessment of the mental acuity of a person they had never met, based on news clips and fueled by political bias. Joe Biden has a well-documented speech impediment. He is a stutterer. The last time I looked there was no cure for stuttering. He has to employ speech therapy techniques every time he speaks. Speech therapy can control stuttering. But the challenges of extreme stress, the need to keep secrets and other issues make being perfect 100% of the time virtually impossible. Every time someone has pointed to a "flub" showing "evidence that Joe has lost it," it is clearly a matter of his stuttering problem.
Joe Biden had a complete physical less than two months ago. In his summary of the exam, Dr. Kevin O'Connor wrote, "President Biden remains a healthy, vigorous, 80-year-old male, who is fit to successfully execute the duties of the Presidency, to include those as Chief Executive, Head of State and ‘Commander in Chief." will take Dr. O'Connor's assessment over yours.