All will come in time.
Export diversification takes time. Apparel is a basic necessity, as is food. Other products are not as essential and not in as high a demand for import in most markets.
Somebody in some US trailer park near a Walmart will buy cheap cotton underwear, which is a disposable item. Better we make it in Bangladesh and give that job to a semi-educated 19 year old female whose only other option was to work as a maid. That will be her ticket to a better life, clean water and hopefully a pathway to educate her kids.
Making higher value addition items in Bangladesh needs higher levels of education and aptitude. Not many have it locally. However they still have to eat. So lower level value addition making cheap stuff is still a viable alternative.
Import substitution in some light engg., and most of the electronics and home/major appliances have already taken place in Bangladesh to a large degree, which are prerequisites for export diversification.
Bangladesh is doing better than most South Asian countries in terms of home/major appliances e.g. TVs, Refrigerators, Washing machines etc. - at least I know one company is.
85% of cellphones sold in Bangladesh are made locally. Ditto for 75% of TVs and Refrigerators. Ditto for many other small kitchen electrics. These will venture overseas in time - they have to. Price/Quality ratio and Bang-for-the-buck quotient will take care of them.
Export of basic software is taking place, even in languages like Japanese and those of the EU. Local software startups are gaining market share and they have a vibrant market locally at least. Bangladesh is the second largest exporter of software after India and has even a bigger freelance export market percentage-wise compared to India, which is the largest exporter.
While I understand your frustration, you also have to understand that certain overseas markets are saturated and have strong players entrenched in them. Those are tough markets to break into. Talking about EU, US and developed Asian countries especially.
To compete in those markets, you need USP's of high quality, attractive modern design and low cost for lower end entry level product. Right now China has that whole sector cornered. No other country can challenge China in those qualities - for now.
Chinese assemblers and manufacturers will venture into Bangladesh to do the same thing the Japanese did for assembly in Vietnam, Thailand and Phillippines - which do have electronics and even camera, drone type products export to some degree but their exports are mostly assembly value-addition related on behalf of Japanese brands.
Chinese business folks have moved some low end value addition (shoes, toys, electronics) operations to Bangladesh, as well as cellphones, but unlike next door in India (which is to serve local market), our assembly operations are primarily for exports. That type of export operation FDI takes far longer to materialize.
This is the reason I am tired of responding to people who say that India gets "x" amount of FDI while Bangladesh doesn't. India gets FDI for serving their local market. Also, their retraction rate for FDI is way higher than for example - China. Google the subject and you will see what I mean. FDI left Indian shores at far higher rates recently, even before covid (Automotive is one example).
Neighboring South Asian countries for example don't export much in terms of electronics into those advanced markets - for example. If they could, they would. But they can't - so they don't even try.
Bangladesh has done a lot in less than five years, and the diversification trend will continue.