Respectfully, I disagree.

Automating the guidance system is not a problem; the FOD check could actually be done away with, and in most other airports is not done, as far as I know (although the last time I saw it proposed a certain "high powered" Nige almost lost his marbles, to the point that I was idly wondering where the defibrillator was on the floorplate). Honestly, some bright mind in IAG was even trialling with HAL an AI-powered camera that would scan the stand and spot anything that could potentially be a FOD... and it worked (it just costs a fortune once you had HAL's cut).

What is the problem is that the FOD check, the guidance system etc are the starting points of a chain of events, namely connecting ground power, moving the jetty, coordinating the movement of cargo and passenger bags and so on and so forth. And those events often do require a "certain role" to do this*. As it happens in most industrial processes, if there's a bottleneck caused by a role's availability, if you don't act on the root cause of the problem you will do nothing but move the bottleneck down the chain. In plain English, you might arrive on stand on time, but then you'll have to tell passengers that they won't be able to get off because there's no one to move the jetty. Work down the chain of tasks and eventually you'll find a task for which the role is required*.

The fundamental issue is that, in 2018/19, below-the-wing operation was hacked to bits. Mr "Cost Cutting is in our DNA" was given the marching orders by Willie, who had unleashed his dog(s) of war onto LHR once they decided that LHR Ops was more expensive than the competition. Don't get me wrong, some reshuffling was needed, and there's an impressive amount of slacking amongst LHR Ops people, and some ideas have actually been brilliant (Mototoks have eliminated towing delays from shorthaul, to name but one). But Operations was seen as a cost centre, not a potential added value, and slashed accordingly. Those who tried to voice concerns about how 'trim' the operation was going to become, and how little resilience was going to remain, were ignored. And now here we are.

There's also a point to be made about the whole industry, not just BA. I don't know if the flying public have understood this, but it's at breaking point. There was a job advert out for Swissport, not exactly one of the worst outfits out there, that basically said "You will be required to come to work anytime, in any weather condition, you will not get car/public transport allowance, in fact there won't be any public transport, you'll have to lift 32kgs repeatedly for 7.5h a day, you will get 30' break and all this for the princely sum of £11 an hour before tax". The job on the ramp is hard, it's dangerous, it wears you down. Guys in their 50s can't bend anymore, walk like their legs are made of cast iron, and given the appalling state of the NHS I had people on long term sick leave for 6 months waiting for an assessment, let alone an operation. And since the pay is so lousy then you can't go private. I heard recently, from HAL, that the ground handlers are effectively still no better off, manpower-wise, than they were 6 months ago. People don't want to join. And they can't increase pay because airlines won't pay more because their shareholders won't agree to have less dividends.

Sorry, it's 7.44 AM and I'm already on my soapbox.

*As an aside, I loathe to defend certain managers, especially one who's now swanning around like Steve Jobs' second coming, but there is a marriage made in hell between managers obtusity and TU inflexibility. Cue the fight to move the cargo dollies out of the path of the aircraft by anyone who isn't from cargo. "I ain't trained for that guv" is the mantra.

Editing to add a response to this point in addition to what Sigwx said.
The jetty failing, at an airport where a jetty is to be used, is a problem and requires a bit of a scramble to sort it out. Once the poor TRM/IRS has realised the jetty's kaputt they need to find a set of steps which, since steps are expensive and you can't have one set on every stand, requires a bit of a faff. There's also some coordination required with the cleaners, who usually board the aircraft from the back on their steps.
Now, the obvious solution would be... why can't the passengers use the cleaners' steps? But unfortunately here's where you stumble on not one, not two, but three obstacles of increasing complexity:
1. BA Brands will object to the fact that the cleaners' stairs aren't BA-branded or 'presentable'. This is easy to counteract since you can a) brand them or b) point out that no one cares about steps and BA steps are often older than those used by the Turks in the 1453 siege of Constantinople.
2. The cleaning company will point out that getting passengers off their steps isn't in their contract and they want to get paid.
3. The lawyers of the cleaning company will point out that their steps are not insured for passenger use, so if a passenger slips and sues them, they're stuffed.